We had the same problem for the first 2 years after moving in. Didn't want to have a terrible relationship with the neighbour (teenage girls with a child), so tried to deal with it amicably, not least because if you want to sell you have a duty to disclose any issues you've had with the neighbours. 18 months, numerous visits to their front door, unable to relax in our own home (cups literally vibrated on our coffee table and kitchen worktops) and a 20 page noise diary later we finally called the council. They were pretty good, got a huge and unpleasant reaction from the neighbour (satisfying), but ultimately we had to keep this up for several months until the neighbour applied to the council for a new flat. It wasn't a great 2 years, and a pretty frustrating process, but worth it in the end and we survived the lottery of the council putting a new tennant in. Now all is peace and quite... sort of.... as much as it can be round here. Good luck!!