13 year old son with aspergers, very aggressive behaviour, father was controlling and abusive

Hi everyone, I just found this site and would really appreciate any support or advice anyone has.  I have 2 children - an 11 year old daughter and a 13 year old son who has is on the autistic spectrum (aspergers).  My ex was very controlling and abusive and I managed to get him to leave 5 years ago.  Since then he has caused a great deal of trouble and I finally have a restraining order preventing him coming to the house or to the children's schools.  The children are no longer required to see him unless they want to (they don't) but until about a year and a half ago, they were required by the courts to have unsupervised visitation with him.  I know that he spent a lot of time messing with my son's head and it took ages to establish this with the court.  So that's the history.  And with that, it probably comes as no surprise that I'm having real trouble with my son.  There's a history there too.  His aspergers makes flexibility very difficult for him.  He has been violent and aggressive in the past.  I have had help a few times from private counsellors who I can ill-afford.  I have also had to call the police in the past and have tried to get help from social services (I ended up really regretting going down that route as they were far worse than useless -positively harmful - I apologise to any social workers reading this.  I'm sure there are lovely helpful people in the service but I encountered some really dangerous and patronising ones).  I have had counselling for the past few years and really see how I set myself up to be in the relationship I was in.  I think I've changed substantially.  My son has actually made real progress in the last 18 months or so - much better at managing his temper and the anxieties that come with the aspergers.  Until now and I think the change is mostly due to hormones.  He has shot up over the summer and his voice has broken and his temper is back on a hair-trigger.  He is kicking doors and destroying my things but has managed to restrain himself to shoving me as he walks by or a thump which is not very hard.  He's being unpleasant to his sister but not physically violent.

So here's what I'm doing and I have a question at the end.  I want him to control his temper and I figure the best way is to make sure I demonstrate that to him.  When he gets abusive, I usually manage to stay quiet - experience tells me that anything else, including any attempt by me to help him with his anger, only escalates the situation.  But he is acting just like his father and it scares me - partly on my account but mostly because I worry about his future.  He has lost all privileges -meaning electronic gadgets in this house and knows he won't earn them back until he can be respectful.  He knows how to be respectful - he is to his teachers.  When I try to talk to him about this, he implies it's my fault for annoying him and that his teachers don't annoy him.  I have tried talking to him about the fact that you will always be annoyed most often by the people you love and explaining that mothers often have to be annoying due to the nature of the job.  This is becoming so long but I hope I've said enough to get the picture across.   Here's one question I have: I lived in the states for 18 years and there is an organisation called big brothers which provides volunteer male role-models for young boys.  Does anyone know of any such scheme over here.  I really think he needs to hear from a man that this is not the way to treat those you love.  And be shown how.  I am going to ask his school whether they have anyone who could mentor him but they have not been brilliant on this front in the past.   I don't have any other family who can help.  My brother was brilliant with him but died very suddenly last year.  If anyone has any other advice or knows of any organisations that could help (I'm in northampton), I'd really appreciate hearing from them as I feel I'm at my wits' end.