1. Keep a diary of all such incidents (possibly backed up by CCTV footage if you're prepared to install cameras) ;
2. Refer the matter to the police:
https://www.gov.uk/how-to-resolve-neighbour-disputes/call-the-police
3. If the problems persist, put pressure on the police (or your local council) to seek a restraining order against your neighbour. (We've got a guy here in Suffolk who knows all about restraining orders!
http://www.eadt.co.uk/news/suffolk-nightmare-neighbour-from-hell-breaches-restraining-order-again-1-5001780 )
(You can seek a restraining order yourself but a court is more likely to look favourably upon an application from the police, or a council, as the court will assume that the police/council have already established that the problem is serious enough to merit such a course of action).