Being an amateur genealogist, I tried to trace William Wilson's family, as it would have been brilliant for them to have the photo. Unfortunately, there is just not enough information to go on. I found what is probably the registration of his death in 1929, and calculated that he was born in 1876, give or take a year. It's possible to obtain a copy of that death certificate, which might give the name of a family member as the informant, but I think it would be a lot of work, and you would need a lot of luck to trace modern descendants. It isn't helped by the name being fairly common.
Anyway, I guess the best place for the photo is with the club historian. Anyone care to tell me how/where he can be contacted?
Thanks for the comments everyone - fascinating discussion.