Peppasmate - Sorry, I have just read that home ed isn't a long term option for you.
But one thing I'd like you to consider is a period of deschooling while you get things sorted.
My DS was 4 when I took him out of school. He had only been 'in school' for 4 weeks (he spent more time being sent home / in the HM office / walking home ALONE (OK he only did that once and it was the final straw for me but still!)
No one cared about him, he was punished for the things he couldn't do and ridiculed for the things he could. At 4, he was violent, aggressive - a danger to himself and others. I could totally see why school wasn't suitable for him. Sadly, the sticking plaster scenario was well and truly alive at our school too!!!
So, after 4 weeks (plus a summer of hell, trying various nurseries to get assessments) I took him out. Until Christmas (so 3 times as long as he'd been at school) he did nothing.
And I do mean nothing. He sat in bed, curtains drawn and played IPAD. He ate when and what he wanted, and never had to leave the house unless he wanted to.
It took me 3 months to get my son back.
Keep fighting (and as Melamineteapot said, you do have to be LOUD!!!) but maybe - just for a while - let him take the pressure off.
My DS is now a very happy 7YO... but I have to accept he is never going to socialise like my other kids. He has very few friends (actually, he no real friends) but that's fine for him. He'd prefer to spend time alone and I have to accept that this is who he is.
I haven't much advice, but always here if you want to rant :-)