^ I think unfortunately that option was not taken & went out the window a long time ago. Good shout though.

I was wondering, surely you have other neighbours in adjacent flats. If these people are making as much noise as you say, why does no-one else complain? Could you talk to your other neighbours to see if they are getting disturbed too?

Like, when you got the police out, one would assume they should talk to other neighbours too to verify the noise levels. Maybe if you had them on your side the police would have a sterner talk with these troublesome neighbours.