Just think it depends on which youth club you went to in late 60's.
Only takes a couple of people to be into soul music [not necessarily embryonic Northern] and there's your gateway.
Certainly my experience. I even dj'd once or twice at a local YC in Hazel Grove playing Motown, Atlantic/Stax and club/Northern like Billy Butler, Fascinations, Tommy Neal, Darrell Banks, Gene Chandler that were still on the shelves back then.
One time the YC must have booked a dj and from what I remember it was early Northern/rare/club whatever like Al Kent and Contours.