We completed on our new flat on Friday and were round there all day with workmen and stuff. We haven't moved in yet. It is a ground floor conversion with only one flat above (old guy - not problems). It is semi-detached and there is just a lady next door on the connnected side (again no problems). On the detached side, it is very close to the house next door (which may be split into flats - not sure yet). There is just a very narrow path between the two of us. I had thought it was a family living there with young kids as there is a trampoline in the back garden and a swing set. We have been at the flat a few times for visits before we completed on it, including one day we were there for about an hour or more with workmen doing quotes and we did not hear anything problematic. But today, when we were there, they had the front bay windows open and were blasting out music really loudly. This went on for hours. I left at some point to come back home and my dh was still there into the evening and it was still going on. He had to go and knock on there door at one point to ask them about water supply so we know it is people living there and not workmen or anything.
So, here is my question: the last 6 years we have lived in flat in a large mansion block. If there were noise issues after 11pm in particular (as stated in the lease), we just called to the porters who sorted it out. In some cases, we called out Westminster noise patrol who were very good. What are my rights in my new situation? Who would I call if I needed to? Obviously, once we move in we will go and speak to them nicely first if they play the music so loudly, but if they do not respond well, then what?