Also you can threaten JR - but the words must be clear ie where they say 'forthnightly speech therapy' do they say 'would benefit from' or is it clear then dc must have it eg wording like 'dc will be given' or 'dc will have'.
Also, is it clear that the therapy must be given by a qualified speech and language theraist? Or would the wording be satisfied if a TA who had read a book was giving it?
Does it say if it should be 1 to 1, or in a small group, or in-class?
Assuming that it is pretty clear that there should be fortnightly 1 to 1 or small group sessions delivered by a qualified therapist, you could try wrting to legal dept saying that the letter/email or whatever has said that dc requires this, and that as the law states that dcs needs must be met, they have broken the law.
You could look to get IPSEA or one of the other charities to do it as a letter-before-action on JR.
JR is in theory availalble as a last resort after all avenues of complaint have been followed but there is an exception for urgent things like a child's education where the time and chance of early intervention can never be given back.
There may even be a way of taking avtion to get the private SALT fees paid back to you - I think a solicitor could look at 'reliance on a misrepresentation'. I know it exists, just really don't have a clue if it would apply to you.