The extract from the Government Guidance Notes for local authorities is below It is called High Hedges Complaints: Prevention and Cure A relevant extract from the 'BRE Guidelines' on light loss is below this

See particularly section 5.83 in the Guidance notes and the red section in the introduction to the 'BRE Guidelines'

Also note that the Law itself is about 'reasonable enjoyment of that property is being adversely affected by the height of a high hedge situated on land owned or occupied by another person'. Nowhere is light loss specifically mentioned.

If the local authority does not keep to the Act and the Government Guidance then they are likely to lose an appeal and the Ombusman could well rule against them. The quotes given below can be used to inform any local authority that the the 'BRE Guidelines' applies only to light loss which is not the whole of the problem with which which the High Hedges Law deals. There is a summary of aspects of hedge nuisance which the High Hedges Law deals in note 5 on Concise Notes but the below extracts from Government Guidance notes are what you need to confront your local authority if it is not paying sufficient attention to your loss of enjoyment of your amenity caused by the height of the hedge.

Extract from the Government Guidance Notes for local authorities

Assessing and Weighing the Evidence
5.54 Having gathered information about the hedge and its effect on both the complainant and the person occupying the land where the hedge is situated, the Council should assess whether there is a problem, how serious it is and thus what weight to give the matter when making their decision.
5.55 The following advice might help Councils to carry out this assessment in an impartial, and broadly consistent, manner. It should be borne in mind that Councils are required to look at things not from the personal viewpoint of the people involved in the dispute but from the objective position of what a reasonable person might expect.
5.56 The list (below) of factors that Councils might be called on to consider is not exhaustive. Issues might occur that are not covered here. Equally, not all these factors will be relevant in every case. Privacy
5.57 On a level site, a height of 2 metres will usually provide privacy from a neighbouring ground floor or garden. 3.5 to 4 metres will normally be enough to prevent overlooking from first floor to ground floor or garden, although this depends on whether the hedge is an equal distance from both properties 22 .
5.58 In general, the level of privacy provided by a 2 metre high hedge is what might reasonably be expected in most urban and suburban situations. A higher hedge height might be justified in special cases, where one property can be seen into more easily than the other. For instance, if one of the gardens is steeply terraced or if the complainant has a balcony or roof garden and the hedge owner does not. Shelter
5.59 A hedge can be an effective windbreak and will usually provide good shelter from the wind for a distance of 8 to 10 times its height 23 . A 2 metre high hedge should thus provide good shelter throughout a garden with a depth of 16 to 20 metres.
Dealing with complaints
21 Section 74.
22 See paragraph 5.1 of High Hedges, daylight and sunlight: Final Report, BRE 2001. The report is available on the ODPM website at www.odpm.gov.uk/treesandhedges.
23 See paragraph 5.2 of High Hedges, daylight and sunlight: Final Report, BRE 2001.
5.60 The size of the garden that is protected by the hedge will, therefore, be one factor in considering what is reasonable in any particular case. Other topographical features and local climatic conditions may also be relevant. For example, a higher hedge height might be justified where the garden is in an exposed position or in an area where high winds occur frequently.
5.61 In addition, it might not be reasonable to expect to use a hedge to provide full protection from the wind if it would have a disproportionate effect on neighbouring properties. For example, if the hedge owner's garden is much larger than the complainant's, perhaps as a result of infill development. Noise, smell, smoke
5.62 Noise will normally pass through hedges. While it is possible to design a hedge as an acoustic screen, it will usually incorporate a special type of fence as well as planting. This is likely to be a rare occurrence in domestic situations. Hedges are also largely ineffective in stopping smells and smoke. Such pollutants can make their way over or through a hedge 24 .
5.63 In general, therefore, it is not reasonable to expect a hedge - whatever its height - to provide protection from noisy neighbours or from the smell and smoke of bonfires or barbecues.
5.64 However, people might perceive that the nuisance is reduced if they are unable to see the source of the noise or fumes. A hedge that is high enough to prevent overlooking (see advice on Privacy above) might, therefore, help to ameliorate these neighbour nuisances. Damage to plants
5.65 It could be difficult to isolate the effects of the height of the hedge when assessing the possible cause of problems of poor plant growth. The roots of a high hedge might also be a contributory factor. They will draw water and nutrients from the soil, reducing what is available to other plants. Under the terms of the Act, however, the effects of the roots of a high hedge cannot be taken into account.
5.66 Where it is considered that a tall hedge could be preventing light reaching plants, Councils might wish to have regard to the advice on light obstruction below.
5.67 They might also wish to take into account that, in general, it is not reasonable to expect to grow particular plants in specific locations or situations. As noted in Chapter 4: Reasonable enjoyment of property, the Act does not serve to protect particular activities that the complainant engages in on their property or specific uses they make of their garden. Whether the hedge interferes with a greenhouse, a vegetable patch, the growing of competition plants or annual bedding will not, therefore, normally be a consideration. In addition, there is a wide range of plants that are suitable for a variety of conditions and situations, offering alternative solutions to any adverse effects of a hedge.
5.68 On the other hand, more weight might be given to these problems if the height of the hedge affects the growth of plants across a substantial portion of the garden, thereby affecting overall enjoyment of the property.
Overhanging branches
5.69 The Act deals only with complaints that relate to the height of the hedge. Problems associated with the width of the hedge will normally not be considered.
24 See paragraphs 5.3 and 5.4 of High Hedges, daylight and sunlight: Final Report, BRE 2001.
5.70 The exception might be where the hedge is so high that someone could not reasonably be expected to trim branches that overhang their property. And, as a result, they are unable to mitigate the adverse effects of the hedge. A person would probably not be able to trim any part of a hedge over 2.5 metres high without specialist equipment or professional help. Whether or not the problem could be solved by cutting back overhanging branches up to this height would, therefore, be relevant in assessing the impact of the hedge.
5.71 Thus problems caused by a hedge blocking a path or other means of access which could be mitigated by trimming branches to just above head height might be discounted. On the other hand, a large overhang that significantly restricted the useable area of the garden, with a consequent effect on amenity, might be given more weight. Litter dropped by the hedge
5.72 Whether litter from an evergreen hedge (eg needles, berries) is caused by the excessive height of the hedge will depend on the particular circumstances. For example, the branches of a high hedge might hang over the roof of a bungalow, depositing litter in the gutters and possibly blocking them. In other cases, the debris could be wind-borne and might not even come from the hedge in question.
5.73 In any event, the volume of litter falling from the hedge is likely to be low. Any resulting problems are unlikely, therefore, to represent a substantial interference with a complainant's enjoyment of their property, though they may be regarded as irritating and inconvenient.
Obstruction of light: windows
5.74 The British Standard Lighting for buildings: Code of practice for daylighting (BS 8206 Part 2) sets the standard for what is a reasonable amount of daylight and sunlight for people to get in their houses. It works on the basis that properties should receive sufficient natural light during daylight hours to enable normal domestic tasks to be carried out without eyestrain.
5.75 In their guidelines on Hedge height and light loss (March 2004)25 , the Building Research Establishment (BRE) have devised a method for calculating what height an evergreen hedge should be in order to deliver to the windows of a house the amount of daylight and sunlight recommended in the British Standard. They are intended for use in analysing the effect on the main rooms of a house (including living rooms, dining rooms, kitchens and bedrooms) and apply whether the hedge is opposite or to one side of the window, or at an angle to it. The guidelines also suggest suitable adjustments if the land is sloped or if the hedge is set back from the boundary.
5.76 Based on accepted good practice standards, the BRE guidelines provide an objective means for assessing whether a hedge is obstructing light to windows. A hedge that is taller than the height derived from the BRE guidelines is likely, therefore, to result in an unreasonable loss of light to windows and so have an adverse effect on someone's reasonable enjoyment of their property. A hedge below the limit is unlikely to have such an effect.
5.77 The British Standard includes recommendations in respect of winter sunlight which, in turn, are incorporated in the BRE guidelines. The hedge heights derived from the BRE guidelines should, therefore, generally be sufficient to secure reasonable access to winter sunlight.
5.78 A lower hedge height might be justified in some circumstances. For example, special consideration might need to be given to properties that have been specifically designed to harness passive solar energy, rather than those which happen to have large windows. Dealing with complaints
P J Littlefair Hedge height and light loss, BRE, 2004.Passive solar properties would normally be characterised by a main window wall facing within 30 degrees of due south, significantly larger windows on the south facing wall compared to the north facing one, provision of thermal mass to store heat, and heating controls to make sure the solar energy is utilised 26 . Loss of solar radiation to solar panels for water or space heating or the generation of electricity might also be taken into account. Normally these panels will be roof mounted.
5.79 In other circumstances, a higher hedge height than that derived from the BRE guidelines might be reasonable. For example, if a hedge opposite a window obscures only part of the field of view; or if there are gaps in the hedge. Obstruction of light: gardens
5.80 The British Standard Lighting for buildings: Code of practice for daylighting (BS 8206 Part 2) does not apply to gardens. The BRE guidelines on Hedge height and light loss, therefore, include a new method for calculating whether an evergreen hedge is likely to cause a significant loss of light to a nearby garden. The approach is based on the daylight and sunlight received in the garden as a percentage of that on unobstructed ground, over the whole year. The BRE guidelines apply to any type of garden, including small back yards with no lawn. Allowance is made for existing obstructions, such as the house and boundary fences, which could increase the relative impact of a hedge. Suitable adjustments are suggested to take account of sloping sites or where the hedge is set back from the boundary. The BRE guidelines have been refined and revised in the light of consultation and field testing. They provide the best available means for assessing the impact of a high hedge on light to a garden.
5.81 In most situations, therefore, a hedge that is taller than the height derived from the BRE guidelines is likely to result in an unreasonable loss of light to a garden and so have an adverse effect on someone's reasonable enjoyment of their property. A hedge below the limit is unlikely to have such an effect.
5.82 A different height might be justified in some circumstances. For example, where hedges cover more than one side of the garden; if there is a building behind, and close to, the hedge; or if there are gaps in the hedge. The BRE guidelines offer some suggestions on how such situations might be dealt with.
5.83 It should be emphasised that the BRE guidelines on Hedge height and light loss do not take account of factors beyond light obstruction and so do not produce general, all-purpose recommended hedge heights.
Visual amenity
5.84 Visual amenity is about what people look out onto, either from their home or garden, and the environmental quality that they experience. It includes such issues as views, whether the hedge is dominant and overbearing or, conversely, whether it is preventing unsightly views.
5.85 Visual amenity is likely to be an important consideration for both the complainant and the owner or occupier of the land where the hedge is situated. There is, however, no objective method for assessing the impact of a hedge on the visual environment. It is a matter of judgement, based on the circumstances of the particular case. High Hedges Complaints: Prevention and Cure
For further information on hedges and solar heating see Annex 4 of the BRE guidelines on Hedge height and light loss and A Review of the BRE Guidance on Hedge Height and Light Loss, BRE 2004. Both are available on the ODPM website at www.odpm.gov.uk/treesandhedges.5.86 Factors that might be taken into account include how close the hedge is to buildings; the height and length of the hedge; its bulk and mass; and the area that it covers compared with that of the garden. The immediate surroundings, especially what else borders the property, and the general characteristics of the area might also be relevant. For example, the presence of other hedges and their impact; other buildings or features which, without the hedge, might be visually intrusive; whether the area is characterised by a sense of openness. Just because trees in the hedge are taller than neighbouring buildings will not necessarily be material.
5.87 The importance of these factors, and their effect on the reasonable enjoyment of the property, will vary according to the circumstances. As a general rule, however, it is not reasonable for someone to expect to see beyond the hedge to a particular landscape, seascape or object, such as an attractive building. On the other hand, it might be reasonable to expect that a property should not suffer serious visual intrusion, which has an oppressive effect on living conditions. Equally, if the surrounding development is characterised by openness, it might be reasonable to expect that the property should not be unduly enclosed by a high hedge. Effect of gaps
5.88 When assessing these or other factors, the effect of any gaps in the hedge should - where relevant - be taken into account. The extent of any gaps and their position in the hedge could be material. In some cases, the depth of the hedge might mean that gaps have little appreciable effect. In others, especially where the canopy is raised, the impact could be significant. Factors unrelated to assessing the impact of the hedge
5.89 As noted in Chapter 4: Grounds of Complaint, some points might arise that are not directly related to the impact of the hedge and so should be discounted. Such points might include:

• fears that the hedge will break or fall;
• that the problems with the hedge have caused worry, concern or depression, leading to health problems;
• that other hedges in the area are maintained at a lower height;
• that the hedge was there before the affected property was built or before the complainant
• that cutting down the hedge is too costly and beyond the means of the person who owns or occupies the site where it is growing.

27 See section 198(6)(b) of the Town and Country Planning Act 1990 and regulation 10 of the Town and Country Planning (Trees) Regulations 1999 (Statutory Instrument 1999 No. 1892).
28 Tree Preservation Orders: a Guide to the Law and Good Practice, DETR, 2000 is available on the ODPM website at www.odpm.gov.uk/treesandhedges.
29 For further information see www.defra.gov.uk/wildlife-countryside/index.htm. 30 See the Wildlife and Countryside Act 1981 and the Conservation (Natural Habitats etc) Regulations 1994 (Statutory Instrument 1994 No. 2716).

Extract From the 'BRE Guidelines' introduction
1. Introduction Hedges have many benefits;they can provide privacy and wind shelter and encourage wildlife. A hedge can also be an attractive feature in its own right. However, very high hedges can cause problems. Often the worst of these is the loss of sunlight and daylight to neighbouring gardens and houses. This Guidance Note provides a way of calculating the height of a hedge that is likely to cause significant loss of light to a garden or house nearby.This method could be used by a hedge owner, or by an affected neighbour,to find out if a hedge is likely to block too much light to the neighbour 's house or garden.
The Note may be used to help resolve cases arising under the Anti-Social Behaviour Act 2003. However the advice given here is not mandatory, and is only one of the factors a local authority will need to take into account.A discussion of the other factors which may be addressed is given in an ODPM guidance document ÔHigh hedges complaints:prevention and cure '.
In the Anti-Social Behaviour Act,"high hedge"means Ôso much of a barrier to light or access as: (a)is formed wholly or predominantly by a line of two or more evergreens;and (b)rises to a height of more than two metres above ground level.' Consequently,these guidelines apply to evergreen hedges.They have not been designed to be applied to individual trees,groups of trees or woodlands. 5 Hedge height and light loss