Having read and agreed with everything said here as it is so understandable , I can only say, through personal experience, that the best thing is to move.
Yes, they are committing illegal and criminal acts, yes, why should you move, yes, they may behave when the BM crew goes round, but......the police expect YOU to produce the evidence, and IF you can, and it GOES to court, and even iIF you win, you STILL have to live next door to them.
Afterwards when you are alone, you are vulnerable.
People like that never change. They remain ignorant, nasty and sly, whereas you, the victim, you do change. You become harrassed, anxious, withdrawn, ill (I developed an ulcer) and you think about nothing but what they will do next, for you are engulfed by them.
But why the hell should you move - you shouldn't. However, I did, and I swapped 5 years of terror for a peaceful, tranquil life ...and it was the best thing I ever did. I never retaliated, so I walked away knowing that even at his worst, he never reduced me to his level...... we are better people than they.
Not everyone behaves badly, I've found myself in an amazing place, with good neighbours..... and so will you.
And remember, what goes around, comes around . Karma is all around us, and one day they may find their selves in a similar or worse situation , and then possibly, just possibly, will realise what a good neighbour they had in you.
Good luck and hugs for you ikate.