Keep a record of the incidents, keep offering polite resistance, keep informing the Police, keep telling the housing association (if applicable) if after 6 months it's still going on complain to the local paper. Apply for harrassment status so you can be rehoused quickly (if that's what you want) although personally they're the ones who should be forced to leave.
Sorry Garner but you're way off the mark, it may only be a bar of chocolate but it was thrown at the window, to have things thrown at your home is thouroughly unpleasant. Home is supposed to be your sanctuary, an oasis of peace in a chaotic world.
Your neighbours sound awful, you can't appease such people or make them understand (you can't polish a turd) you can beat some of them up, they'll understand that, but I don't think you're that kind of person.