Just stumbled across this thread.
My DD went to Limpsfield Grange. It's presented as a panacea for autistic girls but it's not necessarily right for everyone.
They don't focus on academics as much as social interaction and independence skills (which they are very good at) - they only offered a few subjects when DD was there (Maths, English, Art, Science, ICT & catering but ICT and Cooking were basic level BTECs.
DD left with no qualifications at all and she's very bright albeit not hugely academic. She's now stuck at college having to redo maths and English in a mainstream setting and it's holding her back from being able to do her course.
The classes are small so the girls get a lot of attention, but the teaching staff are a bit variable, as are the TAs.
It really depends on what you want? For very anxious girls who need to learn independence skills and build confidence over and above academics, then it's fine. The SALT provision is also really good. If academics are important, or if your girls are interested in a wider range of subjects, then I would say probably not.
It is a unique school as it's the only one that caters solely for autistic girls, but then there's nothing to measure them against. They have a high profile due to media and TV, but they're not a magic school and they won't suit everyone.
I know girls that have thrived there, but for my DD, in hindsight I would have sent her somewhere else.