I can totally sympathise. I've experienced my fair share of wankers - I'm sure I've told you about the pleasures of Bridge of Allan.

I would recommend going to speak to them after work tomorrow, calmly and nicely, explain what happened while being completely rational and personable and ask them to avoid playing music late at night. Certainly mention 'you' banged on the door. Most people don't have the balls to rise to a confrontation and I can almost guarantee you'll get an apology and a desperate explanation before you go further.

If it happens after that, don't even bother leaving the flat and just call the police.

I hope you get a better sleep tonight.