Looks like the guys planning more research along the same lines too so one to watch!
I absolutely agree on your summary of mainstream - you know what my experience of DS's last school was!
In the new school, the head has completely taken responsibility for the provision and organising DS's transition. He is responsive and understanding. It makes a world of difference to feel like you are not only working with someone as opposed to against them but that they understand.
We now call those who don't understand muggles in our house!!