It is these stipulations by the local authority such as saying it must be a wall and not a fence and the fact that this is a new build which is going to be problematical.
There is absolutely no reason why (other than planning consent) the builders cannot build right up to the boundary line.
This little bit of amenity land is not the responsibility of the local authority but your responsibility although you can’t actually do anything with it. In that respect, you can let it go to rack and ruin and get covered in brambles and the local authority can do nothing about it provided it is not covered in rubbish but just overgrown.
In that respect, areas like this are not necessarily a good idea if the landowner decides to ignore it.
What the local authority are after of course is a little bit of a verge to make the place look prettier without them having the liability or maintaining it.
I can see no reason why, now the house is built, that youcould not simply demolish the wall and leave the whole place open plan.
Unfortunately, you cannot build a wall higher than 2 m without planning permission if it is adjacent to the highway which this is.
You may find that in the planning consent, the ability for you to build a wall less than 2 m adjacent to the highway has been specifically excluded.it may be necessary to study the local area plan and your individual permission.
What you may not want of course is a completely open plan garden in the short term.