My son has a terrible EHCP in place (current review at draft stage), but he’s been rejected from a Sen school by LA, and mainstream nursery won’t have him as his EHCP doesn’t reflect his needs - what options do I have?

My son will be 3 in July. His current EHCP reflects very little needs, which is very inaccurate (his paediatrician has written that he needs 1:1 in mainstream, just for context). The LA rejected his school place request at early review quoting the child and families act, but didn’t actually give a reason why. The school we applied for takes from age 3. The LA have said they will consult with the school about looking into the school place April 2025. The mainstream nursery have said they can’t secure extra funding needed to support my son at nursery with his current EHCP as it is, so what options do I have?
I’m very confused if a school take from 3, why we would be rejected now but put forward for consideration next April instead as surely this is based on his current needs?