We have been subjected to anti-social noise from a student house nearby for 4 years. Includes parties until 4am and shouting in the garden. I have kept diaries. The council have been out to witness the noise but seem to brush the problem under the carpet and just send letters which are ignored by the students.
There are a few options and, ultimately, you could take your own action against the occupants and/or their landlord. However I would first go through the Council’s complaints procedures first. If they have witnessed a problem and not taken action they may have failed in their duty. Carry on keeping detailed logsheets whilst the problem still exists. After going through the Council’s complaints procedures you could also go to the Ombudsman if there has been an adminisrative failure.