LA duty to support during school holidays

Good Afternoon
School Holiday Help!
Bear with me it’s a long one, we have 4 year old boy/girl twins. Who are off to separate schools come September my girl the local mainstream and my boy ASD hub another mainstream. For the last 2 1/2 years they’ve attended preschool together, my boy has had a 1:1 for a good portion of that time and although they really didn’t have to they have absorbed the cost for this during holiday club. They are happy to keep him during the holidays but we need to fund 1:1.
I have been trying since April to get something sorted. I initially applied for participation funding but the form was lost, I then applied again and was told to also apply for a carers assessment which I did. We’ve just had that back but it seems the social worker had done an assessment for participation fund which I asked her several times if this was the case as far as I was concerned the participation and the carers assessment were two very different things so wasn’t sure why she was involving herself in it.
We’ve been given 6 hours for 6 weeks only (which isn’t what I was asking the social worker for) my bill for the twins is close to £2,500 for the summer. We’ve had to take a mortgage break to pay for it.
We both work full time and have no family locally and I believe my son should have the same opportunity as my daughter, and our family have the same opportunity to work as other families do (and not working isn’t an option)
I have tried everything we have one SEN play scheme for his age which is only available to book 1 day a week and is grossly oversubscribed. The HAF activities all ask he has a 1:1 and are at schools/playing fields and he’s a runner he’d be out of there. Childminders/nannies don’t wanna know about school holidays only.
I’ve raised a complaint with LA about the way the whole thing has been handled but also about lack of services.
Do I have any more options? What is the LA’s duty in supporting us? I remember reading something in the children’s act about them having a duty to support parents who wish to work/study? Could I call an emergency review of his EHCP to look at the social care element as his needs are currently met during term time we can muddle through.
Erm yeah just help! Thanks if you got this far!