You poor thing. I've been through this but at a time when funding was plentiful a decade ago.
My son was left unattended with a cricket bat.....he played helicopters with it as the blade, with upsetting consequences.
I'm going through applying for EHCP (statement) for another one of my children at the moment.
Can you meet with the schools SENCO and head teacher?
Firstly the school need to put in measures to help your son. They will be struggling for funding and won't want to do this unless they have no other choice.
You need to have a record of all incidents (this will help the EHC application), how and if they were reported, managed, monitored. Dates & times. The other parents may be able to help in a constructive way. They may appreciate you are trying to get more help and funding to support your child in school.
I would apply for the EHCP directly with the LA. If you can, get the school on side this will help greatly.
The benefits of applying as a parent are that you can appeal the decision if you disagree. A school cannot. So all their work applying for an EHCP may go to waste.
You need evidence to apply. Not a diagnosis as the EHCP is based on need not diagnosis. All other reports from assessments (medical, speech and language, psychological, physical) help your case too.
Document everything, make a paper trail. Follow up meetings with emails, follow up phone calls with emails.
I put everything down as a summary and emailed it.
IPSEA (online advice service) helped a lot.
We have been awarded an EHCP at last. I really do understand where you are coming from.