Who provides gel cushions for sofas?

Share your ideas about the practical side of caring.
Having trouble finding out who prescribes/provides gel type cushions for home use?

I've recently got an upgraded wheelchair cushion due to fat loss on buttocks. It's great, but, I do need one for the sofa too.

Was told by wheelchair clinic it was for the GP to sort out. She says she doesn't know, but she'll look into it (that was a month ago). I would push her, but she's already dealing with loads of other, even more urgent stuff on my case.

Anyone know where the gel type sofa cushions are stashed please? (Will swap answer for info on blanket + pampers stashes in hospitals <I've been working on this recently as a side project....making progress ;) )
The Wheelchair Services people will supply my wife's (when they actually get it sorted, it's having a pommel fitted first), but I would have thought other than that, your local friendly Occupational Therapist would sort out any required equipment, that's what happens around here.
I just googled "gel sofa cushions" and got quite a lot of hits for companies supplying this kind of cushion.
If there is a medical need, then the Occupational Therapist should be able to provide it, either through the GP or Social Services