One of the major methods of harassment are noise campaigns. But considering the major problem for gang stalked targets is obtaining hard evidence that they are being harassed, this is one area where evidence can be obtained. Complain, in writing to your landlord/letting agent/estate agent, and keep a copy (where it won’t be stolen – that other problem). Also contact Citizens Advice or any other free legal advice facility. When you complain to the Council, the noise will have inevitably stopped by the time they arrive. But complain anyway, as it goes on record. And have your own record of the sound, ideally with the time, as evidence. They will try to ignore you, and fob you off, but keep at them, and keep records of all encounters. If nothing is done after a reasonable time, call the police. The point is to get it down on official records acknowledgement that you are being harassed. Don’t retaliate in kind, as any complaint about you will be responded to. Noise campaigns can go on for years. The longer they do it, the more evidence mounts up.
This is only one part of the problem of vigilante stalking. But if you break the problem down into its component parts, you may make a start at countering the problem. Getting evidence – about everything – is hard, but it is the most important thing you can do.