Can't help with the name of a surgoen, sorry, but Stanmore shoudl definitely have an ortho who understands HMS. My DD1 had her spinal surgery done at Stanmore and we were really pleased cos she had an ortho who understood HMS, so they do exist. I know there is a shoulder guy there who understnds HMS too as he was reccomended by the HMS clinic at UCHL. Maybe ask around aqt Stanmore? I know it is a pain travelling from W Wales to Stanmore but they were excellent at providing ambulances to transport my daughter - 3 return trips in total.
Diagnosed HEDS December 1st 2005. DD1 (20) HEDS and scoliosis (now corrected by surgery), diagnosed June 2006. DD2 (18) mild HMS. Son (11) some hypermobile joints, poor muscle strength and seems to be developing scoliosis as well, woopee!