I suppose only by ringing the Planning department/Land registry will I know for sure but I thought I might ask in case other members have been in a similar situation.
Our bungalow has a burn at the foot of our back garden and across the burn there is a newly built house, which has been for sale for four or five months, and that house does not not have a bottom fence.
Fortunately by judicious planning I have established quite a good hawthorn hedge (only four foot high mind) on my side. This combined with the self seeded saplings on the other side of the burn affords some privacy but it is not 100% and I can see their backdoor quite plainly and, of course, they can see mine! I do not like my privacy violated as it were.
What attracted us to this bungalow in the first place was because across the burn, behind a straggle of trees was an old fashioned country garage stretching across three house widths - complete privacy. When they pulled it down they also cut down the trees which fortunately have come away again.
Getting to the point, does a newly built property, which faces an established dwelling need, by law, to have a back fence?
I would have thought it does as their garden runs down to the burn, as mine does!
I am not aware of any law which says that a privately owned property must be fenced. In fact, many houses - especially those built on estates - come with a restrictive covenant expressly forbidding the erection of fences at the front.
Putting up fences is a convention, originally brought about mainly by the desire for privacy, and to delineate the extent of an owner's property. The advent of the Land registry largely did away with the need for fences, as each property's boundaries are recorded.
I doubt that you can do anything about the new house, apart from putting up your own fence if you feel you need more privacy. You may need planning permission to plant a hedge, so it's worth checking with your Local Authority.