how old is your ds?
do you already do ABA at home?
is yuor ds in any other provision at the moment? (pre-school/nursery, etc?)
dd1 started at ABA school last December, when she was 5.4 (we basically refused to send her to the school LEA wanted, and self-funded while we fought for ABA school named on Statement)
whereabouts are you in Statemtning?
what we did, which took quite a while, but has been worth it in the end, was to prove that La preferred provision failed dd. so we sent her to MS pre-school, while doing ABa part time at home, and paper-trailed the fact that there was no progress at MS vs lots of progress at home.
we then moved county (long story!) and sent dd to an ASD pre-school, which, if it had worked for her, would have meant dd going to the LA ASD provision (very sought after, parents figth tribunals to get in, always over-subscribed)
ASD pre-school didn't work out (teacch based, and again no progress, as openly admitted by pre-school). we re-started ABA, and progress took off again.
La ed psych assessed dd at pre-school, noted all the issues.
then saw her at home and was blown away by the difference (open, happy, relaxed, chatty - getting him to join in with her games, etc)
he then saw her at ABA school after she started there, and was even more blown away.
we had to threaten Tribunal, and apply, etc - gather evidence, but LA settled well before date.