Only just seen this post but my son (fairly recently diagnosed) has had an OT assessment at GOSH and it has been very useful. As we'd never thought of him as hypermobile until recently, my OH and me had just thought that our son's handwriting was (a) quite poor and (b) deterioriating rapidly over a piece of writing, because he wasn't very interested in making it neat. At the OT assessment it was established that it is hypermobility causing the problems due to unstable joints in wrists and fingers. After this he got a letter for school to allow him more time for exams where sustained writing is needed (useful as he's in Year 6 and about to do SATS). The OT has also said he would benefit from the use of a laptop in future and will write a letter for us to take to his secondary school to try to get this sorted out (NB not everyone finds having their own laptop useful due to the weight of lugging it around so not sure as yet how this will be organised). There are other things that she looked at to do with pen grips, theraputty and other items plus exercises to help strengthen fingers etc, and we may be returning to look at other things such as bathing in the future although it's a bit complicated due to other problems.
I found the whole procedure very helpful and positive. My son detests hospital visits but he sees his OT appointments as more positive than anything else which for him is the highest praise.