Son struggling to leave the house and School refusal

Hi everyone

This is my first post and am a bit nervous! 

My 10yr old Son was diagnosed ASD a year ago.  He if very High Functioning and his masking (particularly at school) has led to no help or support.  For the last 6 months he has shown a marked increased in compulsive behaviour indicating his stress was rising.  School dismissed my concerns as they 'see nothing' despite him being late into school for most of the year.  He is now struggling to leave the house for any trip and has not attended School since the end of May. He says he will never go there again.  We tried to get him to an Assessment day at a new school which is specialist, as he said he wanted to change school, but that was a disaster and he was traumatised and doesn't want to go there now.  Also they say they think they can't meet his needs now because of his reaction.  

He  uses delaying/avoidance and compulsive behaviour/rituals when we try and go anywhere and now he just refuses and is very defiant if he can't face starting to try.  He is desperate to stop anyone knowing that he has any differences or difficulties and is distressed and cannot communicate to us what he is feeling inside other than 'bad' and 'unhappy'.  The compulsive behaviour he calls rituals and sometimes they calm him but when leaving the house they can distress him and he can end up re-doing them time and time again and you can see he is struggling so much.  If he can't 'feel right' about it then he can end up in tears and staying home.

GP has referred us back to CAMHS (they did original assessment) but we need help quicker than that.  Not sure what to do or where to go.  Thinking of finding a private Psychiatrist but as he does not open up to anyone, not sure about that.  Has anyone got any ideas please?