And now, 18 years on, he has been back in touch with another mystery picture which he is trying to identify. It shows a little boy climbing what look like steps cut into a sort of mini cliff, and John thinks it was probably taken in Shropshire or on the borders.
John said: "Some years ago you assisted me, with a little help from your readers, in identifying a building and gardens from an old lantern slide. It proved to be Stokesay Castle.
"Now I have another quest. This is not a lantern slide but a snapshot I took in the early 1980s on a visit to the U.K. from Canada. I am 99 per cent certain it is in Shropshire, maybe near Chirk.
"This shows a sandstone face with a series of what I can only call footholes of varied pitch running in parallel to the upper level. You may well guess my double-barrelled question. Where is it and what was it?
"In spite of a lot of internet trolling I can find no reference to this feature so it may just stump your readers, although I somehow doubt it!
"Kindest regards from the Frozen North."
Well, can you identify it? If so, do drop us a line, or you can contact John directly at email@example.com by email.