It reminds me of Ray Bennett's motor bike shop in Spon End. Over the years, I and my associates invariably got the same answer from the big bloke who ran the shop:
"I'd like a clutch cable for a Bantam D7 please".
"Ordinary standard one'll do you mate!"
I worked at Albany Motorcycle Spares in the mid 60's and the stock control was almost non-existent which meant that if you wanted a cable for a bike other than a popular Triumph or BSA it was pot luck that you got the right one! Invariably, it wasn't the right one so the customer would bring it back with the original and we would make one up for him. No-one complained in those days, they just thought you were a great bloke for fixing them up with what they needed.