Thanks for your advice.

To clarify, it's actually a maisonette I live in. Similar to a flat/apartment but with own front door direct from road, rather than accessing through a communal entrance. I own my property, the people above are tenants. I also know their landlord, as she's my late neighbour's daughter-in-law. Sorry, forgot to provide explanation.

I've decided to have a word with them tomorrow. This can't go on. Don't want to involve police , they've got more important things to do over here. If unsuccessful, then I'll talk to their landlord, as we always got on well.

Thanks for allowing me to vent my feelings!!