I have no suggestions but I wish you the best of luck.

Honestly, I think the comments about your neighbour being and "idiot" or not being fair are not justified. It is your responsibility to take care of your cats. And correct me if I'm wrong, but there are laws against them being outside anyways? I would be peeved if some cat came and scratched, messed up, or ruined anything of mine. You guys should all try to see things through his eyes. Would YOU like to be paying for damage repairs that came from someone elses cat!?