I have an Autistic and an Aspergers child at home. I was so fed up of the abuse my autistic son was suffering at school because his needs weren't being met even though he was on Action plus, that we took him out of school and Home Educated him (Home Schooled). We have never looked back, he may not have got any exams to wave at people, but he wouldn't have had them anyway (low IQ). What we do have is a mature lad who knows what his problems are and who has grown up without the stress that an autistic kid usually suffers in a school setting. So his personality has been able to integrate better instead of being shattered with having to wear the masks and armour in school that autistic kids wear. His anxiety levels are much, much better than they ever were and his 'meltdowns' have dropped from every day to once every 2 months or so.
The school may not actually see any problems in your son. He will behave impeccably in school, holding in all the stress and anxiety, trying desperately to appear and act 'normal'. Yet as soon as he's safe at home the dams burst and you are left trying to deal with meltdowns, physical attacks, self harm, anxiety, stress, not eating, making themselves sick, the whole mess that attending school does to an autistic child. But the school never see's the after effects you have to deal with so they don't ask for the funding or the extra help that he needs.
When we took Martyn out of school, he was so badly traumatised that if we sat down with a book, any book, with him for six months he would burst into tears. We had to get a private diagnosis to get a decent report about his problems, all we had ever had from the Child Development Centre and the school was a one paragraph note that 'he seemed to have problems with socialising'. The private report we had was 16 pages long, it explained what they had seen, what they had tested for and they explained what the results meant in plain English, the most telling was that Martyn was profoundly Dyslexic, which the school had never picked up on. At the end they also suggested way of helping Martyn plus lots of books to read and organisations that could help. If you can afford it, get a private test done. If you can do it, look into Home Education as a way forward for his education. Right off my soap box.