Deleting this old post
Hi Mhairi
I thought this information line could be of use to you:
http://www.autism.org.uk/educationrights
It's for the NAS Education Rights Servive who'll be able to give you some advice about finding the right placement and support - there's a number specifically for Scotland.
Hopefully some of our users will also have some experience to share with you.
Good luck with it all.