Older children with cerebral palsy - exercise questions

[HairyMaclary]

I used to be a very active member of this forum but dropped away as DS got older and I got more used to managing his needs. I don't know if any parents of older children with CP are about though as I could do with some help.

DS is 14, had SDR at 7, now growing lots and likely to need further ops to release tightness in calves and hamstrings, usual CP story. However he won't engage in physio, a hangover from the post SDR rehab when, in hindsight, we probably pushed it too far. We need to find suitable exercise that's fun for him but I'm really struggling to find the entry level wheelchair racing, race running etc clubs that he might like for the social side too. Does anyone know how to get to them? Anyone know if anything in London or the SE?

Also - has anyone used a personal trainer at a gym? Has that worked with an (emotionally and socially immature) teenager?

Any other ideas? Thanks!