Dear [Name or House Number],
I am writing to let you know that the trees in the back of your garden are causing [describe the problem].
Could you please let me know if any of the trees are, to your knowledge, protected by a preservation order. If they are not, I’d like to ask for maintenance to be carried out to reduce the height of the [trees/bushes].
I have been informed that if you don’t take action, I can complain to the local authority, as I believe the height of the [trees/bushes] breaches their regulations.
Therefore, unless they are protected, can you please take appropriate action to reduce the height of your [trees/bushes] as soon as possible.
I look forward to hearing from you within the next 14 days.
Should you refuse my request, I shall refer the matter to the local authority who may then issue you with a formal notice setting out what must be done and by when.