Neighbors

Hey ladies
I live in a unit complex of 20 houses on New Year's Eve i had a neighbors over with there daughter so us adults could hangout and the kids could play (I have a son) and the two kids where going between my back and front yards and the neighbor that was over front yards with adults supervision of course and another neighbors grandson is going in and out on a trail bike that is unregistered and he was speeding in and out and this was making the kids really scared we have asked the grandparents in the past if he can not ride it in and out of the complex due to the kids being scared and other neighbors being old and a number of us being fed up with it and at first they where fine with it and he started it out of the complex .
Then on New Year's Eve he started with it again after being told numerous times not to by other people that live in the complex, his grandparents and the police well this time my partner ring up the police to see if they can sort it out as he has not listened in the past and that we are concerned for the kids they sorted it out and then last week when he was at his grandparents house he hit my partner because of it to me and the other neighbor that was over at mine at the time my partner only rung then out of fear that the kids would get hurt ( there wasn't any cars coming in or out by the time he started) and at the time he hit my partner i was furious (I wasn't home i was dropping my son off at school 40 minutes away by public transport) i had rung housing ( as they are owned be housing nsw) and told them everything i had been told the police where also told and not iam afraid that he is going to get his crew together and come and do something to the house or the fact we are going to get kick out i told housing the truth and they told me that they will talk to then as they see that as antisocial behaviour on the grandparents behalf and they could lose there house (under the new laws) but i am still worried about it all and i don't want to move as my son is settled here and he has autism so i don't want to move and up set him in doing so