Warning! not legal and definitely not PC
I realise that moving may not be an option (and I hate to let anyone or anything get the better of me) but I reckon with kids, staying there should not be considered an option. However this is what I reckon I would do:
Slowly empty, or partly empty the house, but don't make it obvious. Go down to the local Harvey Norman or similar and get a whole heap of appliance boxes. Parade them in (preferably so that the scumbags can see it) so that they think you've loaded the place up again. Get a heap of mates around and sneak them in. Remove the family. Wait. Let the scumbags break in again. Trap them in the house (some of the mates come around from the back and bar their access) lay into them with boots and bats, and tell them they'll be killed if they're seen in the vicinity again. :eek:
Okay, flame away.
Years ago at school, a bully walked up to me as class started and told me to move as I was in his seat. I knew that if I complied that I'd cop s**t from him forever (or at least for the rest of school, which is forever at that age. I told him I wasn't moving, he (without warning) smacked me across the mouth with a cricket ball and kneed me in the face several times (apparently). I came to in the sick bay with blood all over my shirt. The deputy quizzed me and I said I must have had a fall.
The next week I got a cricket bat out of the sports store and brained the guy with it. When he came to I told him that he might be bigger than me, but if he F###ed with me again I'd kill him. He and any other potential bullies stayed clear of me after that.
Mick
Disclaimer: I do not condone or promote violence as a solution to problems, any problems should, of course, be referred to the police.