They were a reasonably common (or at least not rare) part of the landscape in BC (don't know about the rest of Canada) in the 60s. Around Victoria (where I went to high school), British cars were pretty common in the 60s and 70s. I'd see Humbers, Hillmans, Vauxhalls, Austins, Morrises, Wolseleys, Rileys, etc on a regular basis. Our vice-principal drove a Vanden Plas 4 L to school every day.