Problems with Behviour 4 year old at School

My son has been at Primary school now for 3 months and is going through a Special Needs Assessment at the min he has classic autism.

The teachers at his school know little about his condition or how to react to a child with autism.

Today at school he kicked his TA (personal teacher) in the face and split her lip she was trying to change his pull up also at playtime he scratched another child down her face because she wouldnt get off a bike they also had to psyically pick him up and take him in after playtime.

His behaviour is getting worse and although he has limited speach i have been trying to get him to understand its wrong. the way the head teacher dealt with ben is remove him all together from the class and sit him in her office until he said sorry.

I don't really know how to deal with behaviour and i couldnt give her any tips it is very unusual for him to be voilent at school as at home he doesnt tend to kick out of lash out just a lot of screaming.

Does anyone have any tips on how to control this behaviour or even why he is being like this!