All sounds very familar to me.
We were sent to CAMHS too, ds had a year and half's therapy there to deal with his anxiety, caused by school.
What i will say, is that ds's old school also reported to CAMHS that ds didnt have a problem, i did ie 'over anxious' and ds didnt not have a diagnosis at the time either. My parenting skills were very much under the spot light.
I also found that CAMHS did not disclose to me what school were saying to them ie i was the cause of ds's anxiety, so i could not dispute this directly. It was an uphill struggle.
But what i will say for CAMHS is that once ds began having weekly 1:1 therapy with CAMHS and also got to know me a bit too, they could see that school was the problem, not me. Ds also received his official dx during this time too, which helped. It took them a year and half and for ds to move schools, before CAMHS would finally speak up and say that difficulties in school were the cause of ds's anxiety and that moving school was a positive step for ds (they put it in a very nice way of course) and they supported my application for a statement.
Even with the support of CAMHS and them saying it was school and a dx, i still had my over anxious mother title and the Local authority 'referred' to SS 'to help mum deal with her anxieties' (i wasnt supposed to see this). I declined their offer of 'help', unless we are talking child abuse etc, you can decline.
While ds was at his old school, CAMHS would not support my request for ds to change schools. They will not get involved in school disputes.
Ds began refusing school, i tried to sort it with school and copied in the attendance officer, they took the same approach as they did to bullying. So i removed him.
What do you mean you have to give 6 weeks notice?
As long as you have written down and you have told the school, it doesnt matter if the school record it. The record is you reporting it to the school in writing.
You have the right to home ed your child, even if that child is not being bullied or having any difficulties at school whatsoever. Its a choice parents can make regardless.