I've a vegetarian, don't agree with breeding animals just to be killed, but I'd have no problem with someone going around getting rid of a pest problem. Council have been asked for, well, decades to do something about it though and they refuse to do anything.
Get a gun or borrow a friends. Air rifle or real gun. Air rifles might kill them, or it might just be a bit unplesant, either way, you hit htem and they won't be coming back anytime soon.
If you're going in for the kill then you should really got a friend or pro pest controler with a proper gun to sit out in yoru back room with some IR goggles and a brandy and kill them all.
If you kill the moter one and then leave it then the rest should come looking for it, then take out the lot.
Might sound cruel but its the best way, and they are a bloody pain.