Staff will need training on communication and understanding autism. In addition I would suggest personal safety training (Team Teach or similar) to show school are looking after staff too. It is a head teacher decision if they can have the child in due to health and safety but you really need to exhaust options first. What do parents want? As others have said, if it is more than 8 weeks since the final EHCP you’d need a review to discuss change of placement. Parents may need support via SENDIASS/parent partnership as you can’t do that bit really – needs to be independent so parents don’t feel bullied or coerced . Make sure you keep things documented. Don’t put emotion or your interpretation of behaviour – just facts.