mainsteam school to special school.

I've found a school that would meet all of my daughters needs, its a mainstream school that has a specialised asd unit. Im in the process of changing part 4 of her statement can anyone give me a rough idea how long it will take for the ammendments to be made?

I've also been informed that could be hard to get into this school as its not in our catchement area even though it is still close to where we live. The special schools that are in our area take children with asd but also with learning difficulties which my daughter doesn't have. Has anyone else been in the same situation and was it a success please let me know, thanks.x