OP, did the NHS OT give you any discharge info or anything in writing? It maybe that you will need to pay for a couple of assessments yourself if you end up appealing. There is a charity which can help fund these. I can't remember the name and just googled it to no avail but they sometimes get reccomended by sossen.
Nhs reports aren't always as detailed, thorough and specific as they need to be. Sometimes if they have long waiting lists in your area it can work to your advantage as you can use it to get the LA to commission independents.
Hypermobility can be incredibly painful and tiring. Do you have anything in writing from the school, maybe a report or email that says he uses his current grip for neater writing? OT's can detail provision to help but they will need to assess. Things like pencil grips, finger exercises, core strength exercises, specialist seating, a scribe, voice recognition software... my son uses a laptop as its easier for him to type than write. This is in section f including the programmes tgst he uses so that it is provided by the school. It comes home with him too. He's had one since year 1.
He clearly has sensory needs, when you ask for the assessment you'll need an OT with post graduate training in sensory processing to do the assessment. Some LA'S don't commission these so again if needs be you'll need to get them to buy in. Do you have any evidence of his sensory behaviour that you could use to submit? Again maybe school reports, his diagnosis report, minutes from any meetings?
You could trial him with ear defenders in the mean time, just if he wants to go anywhere noisy so that he can. Noise cancelling headphones are quite trendy at the mo so he needn't look like he's wearing them for this reason.
As I said earlier, ask for a sensory OT assessment as well as a norm OT assessment, speech therapy assessment and educational psychology assessment as a minimum. Make sure they assess using established/ recognised tests and not just observations. Anything they feel he needs should be detailed as a provision to meet need and is not a reccomendation. (You do not want the ehcp to say it is reccomended that.... as this is unenforceable likewise wording like may benefit from, sometimes,frequent, often, as required....) the provision needs to be worded so that there is no doubt as to what is provided, for how long, by who, when, what training is required, who oversees plans and reviews them etc.
If the teacher speaks to you in regards to anything maybe just follow it up with an email saying something like " hi Ms. Xx, I just wanted to make sure my understanding of our conversation today was correct. My ds ran out of class due to...., you are doing yyy to help". This way you're building up evidence and keeping a record if things are being said verbally.
If he's having to leave class regularly then this is a clear sign of unmet needs. See if you can get school to write this down too somewhere. You could ask for these times to be documented as he's missing out on education. Ask them why he's being sent out, is it punishment? What they hope to achieve by doing this? It sounds like he needs time to regulate because he's struggling because his needs aren't being met. Incidently if it is punishment and he's being sent to isolate that's a whole diff ball game as a child shouldn't be isolated regularly and the school should put things in place to stop whatever is causing it, they should also be providing suitable work so he isn't missing out on education znd make sure he's suitably supervised by someone qualified to teach. There was new guidance released on this near the back end of last year. If they say he needs a break then that's evidence.
Your son isn't hard work. He's not having his needs met and being expected to function. It isn't right. Your son does have needs. It isn't about who has the most complex, it's about each child getting an education. Their needs are different but your sons aren't less.
You have had some great replies on this thread but please call ipsea or sossen. Their advisors are trained and will be able to go through things with you on a personal level which you won't get on here. Have a look at their websites too. Also specialneedsjungle.
Ignore the posters saying he won't get one, he's too academic etc.
Start as soon as possible, avoid sendiass.