I am not quite sure how much they actually can cut. There are local formulas for the bit of a school budget that is notionally for sen, but I don't think they can not give this money at all and academies aren't funded via the lea.
In terms of other aspects of sen funding a lot of it has statutory frameworks.
I think they'd need to be able to change the send code of practice and the national funding formula to really impact it.
That's not to say I dont think they will be hostile and actively try to minimise costs where they can, but LAs are already like that, especially if they are a safety valve area.