I'm so sorry!
I have to recommend Maya's blog: loving with chronic illness. She has been dealing with spondylitis for quite a long while and she is in college now. Her blog is a wonderful resource for connecting others, I've found.
I wish I knew more about the school system in the UK but here in the states we can have a 504 B plan, that is less involved than an IEP, but can help a student get the support she needs. You could contact your special education department if you haven't to find out about your options, which may seem kind of not necessary perhaps but just may help.
She can come here and get support, too!
Nice to meet you and my heart goes out to you and your sweet girl,
