I have been through the IHR process once already with a diagnosis of ME/CFS, it failed. It was a long and drawn out process that centred around the issue of permanence, the diability was agreed early on. To be brief, it failed as they felt that despite all of the CBT that i had, had i didn't have enough and that despite medical evidence stating that i wasn't suitable for GET, i had to do it as it would 'make me better in six months'!
The process is incredibly corrupt and they will use any excuse to not grant it, you really do have to cover every angle in order to put them into a corner where they literally have nowhere to go but to say yes. I have now done more CBT and completed a course in GET, against my consultants advice and it has made me a lot more ill and a lot more disabled, angry is not the word right now! To cap it all, my Force have put me on Stage 2 UPP and are giving another action plan that i cannot achieve. I honestly am at the end of my tether and beign pushed into a very dark place, i honestly don't know what to do to get them to actually help me. If you or anyone else has any idea or know's anyone who can help with disability discrimination, i'd be really happy to hear from you.
I wish you luck with you application, just pelase consider the above and get advice from the ME Association, they are really good with advising what can possibly help.