I always ask for "Whitworth Spanners". Then when they produce them I check carefully while I still have a hold on the money.
Many, no most, of the traders then proceed to hand me a set of spanners marked up with the designation A/F. When challenged they usually respond with ".....but you asked for imperial spanners". Are they deaf or daft? Probably both I fear. What I always ask for is Whitworth Spanners.
So many traders are merely selling stuff, and they really have no idea about the rights and wrongs of the equipment they sell. I blame them smart phones, which apparently are not so smart as they make out.