GREAT picture! It is really emblematic of the olden days when parts were so scare and AH Spares was a godsend. By the mid-1970s the BMC (well, BL) dealer stocks were drying up fast, and it was before several companies began to reproduce so many parts. We cannibalized a lot of cars in the 1970s in the quest for parts to keep others running.
I first visited AH Spares in November 1985 (it as a dark and stormy night), but I received a friendly greeting and was happy to see so much activity including a couple of containers being filled with parts for shipment to Moss Motors. By then the parts picture was definitely improved, and it frequently amazes me that it only continues to improve (haven't they all been restored, at least twice, by now?).
If I'm not mistaken, the last of the original AH Spares crew, Gordon Barton, retired just a few years ago. He was a direct link to the Donald Healey Motor Company. It was somehow comforting to buy Healey parts across the counter from a former Donald Healey Motor Company man. Bob Hill, the nephew of Fred Draper, the founder, was still the boss when I was visiting in the latter 1980s during stopovers between the USA and east Africa.