Ah yes the Mecca. Was it Ron who would wander off into a dark Aladdin like cave for a BSA C11G head gasket set and come back, slap it on the counter and say: "There you are me old China ..."
The Mecca was famously on Mill Street, but before that it was on Market Street, pretty much next door to Lloyds Bank, before all that side was rebuilt. Kept some of the old bangers I was riding throughout the 60's going. (Triumph Tiger 100, BSA C11G, BSA A7 and A10. Ariel Red Hunter, BSA B32, Norton ES2 .... and on and on ...)