Some more info and further to my post 35.
Carl Meyer is (primarily if not exclusively) hips and knees. That said, on my referral to him from my GP, he (Lt Col Meyer) referred me internally - within the hospital - to a foot man and a shoulder man.
So - for me anyway - the initial referrral was to the Veterans Unit, but worked onwards from there - especailly for my shoulder which is now titanium and plastic!
And I am now officially 20% disabled for service-attributable reasons, so get a small - but usefully tax-free - War Pension. Also - thanks I think to BoJo when he was Mayor - I get a totally free Oyster Card for free travel in and around London, 'busses, tubes and overground.
Happy to attempt to answer any further queries if I can, either publicly or by PM. I cannot sing the praises of RJAH too highly.