I’m sure motability would take in to account your wifes condition if that was needed however, it could be your jumping out of frying pan into the fire without further advice –
Zero gravity and fluid chair seat and wheel chair cushions maybe worth a try, as theyre proper medical cushions and mot cheap. Remember my dad having them when his cancer first moved into his hips and these cushions were changed/adjusted to the level of pain and always had one with in when he traveled in the car and he found them, shall I say comfortable in a more pleaant bareable situation, that allowed him to do hings and he carried on with life right up to the end.
I can’t fully remember, but I think my mum refered to community OH, who provided these cushions and much more. I can ask mum if you want, as the system will be the same for Staffordshire, as they were only up the road in Newastle.
Mum would also insist on going private for initial consultant consuiltaions and jumped back on the NHS for tests and scans which were allways within a fortnight and if treatment was required, it was far quicker than waiting on a long list, for dads other issues.
This actually might be a good idea for a couple hundred quid if only to get a different opinion and a few tests much quicker than normal!