The OP mentioned that the father replaced most of the parts over time, as most riders would during that period if they continuously rode. I obsessively watch eBay UK and get the VCC quarterly advertisements, and what seems to be a primary reason why most dealers selling postwar British bicycles as framesets is because typically they are no longer equipped with period-correct components, which is obviously the fashionable thing to do these days when restoring them. The 1954 Carlton Super Python I just refinished was on the road until just before the dealer sold it to me, and it was equipped with a mix of 1970s-80s components that the previous owner was using to keep it reliable. That's a common story for nice older British frames, which individual men or multiple generations of users have kept on the road for decades.

I see no reason why a Canadian rider would not follow along in that fashion for at least some time! The Bates looks well equipped and that's a lovely example. Other users have already filled you in on the details, so good luck with whatever you plan to do with it. Cheers!

-Gregory