The whole process is really shit, so please don't feel unintelligent or anything. If you're not already in some knowledgeable Facebook groups, I'd look at joining some. Educational Equality and EHCP Parent Support Group are two that offer general advice, you may be able to find one specifically for your local area too. Get advice on the draft whilst you have time. Any non specific wording will need to be tightened up.
What I mean by non specific wording is helpful to think about in terms of a job contract. Would you take a job that offered...
"Opportunities for" a lunch break
(No, you'd want it specified that you have a 30 minute lunch break once a day)
"Access to" necessary equipment
(No, you'd want to know that all equipment/uniform etc. for your role was provided)
"An appropriate" salary
(No, you'd want to know what that salary and how often you'll receive it)
I had to go through a whole mediation process just to get the words "such as" removed from my sons EHCP. I am buying a lottery ticket today. I could win a prize "such as" a million pounds. I could also win a tenner.
Any ambiguity or room for interpretation needs to be amended. You can't just make stuff up, but you should be able to reference back to things in the professionals reports.
If its not specifically written in the plan, the LA are under no obligation to fund it and the school is under no obligation to provide it, so it needs to be as watertight as possible.
I'd also brace yourself that you may have a fight on your hands for a specialist school place sadly, but I have my fingers firmly crossed for you 🤞