I am going to tell you a secret. Been there and done that lol and it isnt as bad as you think x
Correct protocol have you emailed the HT with your concerns or do you think its gone beyond that now. If you have then great.
Like Ellen said call an emergency review but do it in writing or email as you need a paper trail to cover your back.
State in the email to the LA that you consider your sons safety and well being to be at risk and state your reasons and examples. If you feel the statement is not being adhered to then state so and again which parts and the reason why to see it not being met and the end result of how its affecting DS.
If you have had a convo with HT/SENCO then put that in word for word. I then copied the HT into the email to the LA to show its transparency and that you have nothing to hide or alter that its all fact. I politely put at the foot that this you consider to be an emergency and that you are now keeping your son home until his needs are met and his safety is assured. Then put that you would much prefer your DS to be in school so you look forward to hearing from them with an appointment asap. Give them 3 days and then ring.
Always keep in your head that the LA is responsible for your sons education and welfare so that includes safety. If the school dont follow the statement then the LA is at fault so the onus is on them to put it right.
This should rush things through a bit for you.
If you really dont want your son there then the school has a chance at this meeting to say they cant meet his needs and their reasons for it. This could possibly give you a chance to request a school move?
I took a gamble and home ed my DS there was no way his school were ever going to agree to care for him and support him correctly but they changed to an academy.
It gets different then as it is entirely up to you how you wish to move on. I took my son out but I volountarily home ed and that meant that his school had NO RESPONSIBILITY or ties to him anymore I plainly de reg him. In writing I put that I was pulling him out of school to home ed until transition to his new school but he was due to join juniors and so that could be different for you if you have no move in place. Plus keeping ties with crap school can mean they are still responsible for educating him and maybe home tutor? or at least educational supplies. But I would see what LA brings and what idea you have of the way the review is going then come back and someone more legally minded can advise you and give you more ideas to work from.
In other words go with the flow as what works for one parent may not for another x follow your instincts and the more options you can have to choose from the better. I expect more will post tomorrow with a bit more experience from different angles. Good luck :)
Good luck.