If they do not have import marks they are pre 1969 imports. Enfield rifles that came over to the US that did not come out of UK sales will lack the Commercial proofs (London or Birmingham). Most of the British Arms in Canada, not of Canadian origin, came from the same commercial sales in the UK from ~1954 to 1968.
The two most obvious candidates for sources are Holland and Belgium, both of which received sizeable stocks of British arms from the UK and Canada. No idea when Belgium sold off their arms, but Holland most likely sold theirs off post 1960 when the reequipped the army with FAL rifles. One of those countries, I forget which, got most of their UK equipment from Canada.
Another possibility is Denmark, which had a number of No4 and No1 MKIII rifles which according to the Danish arms site they got rid of in the early 1950s (1954~55?) to Interarmeco. it was at that time Denmark got rid of the Swedish M96 and other obsolete arms, and reequipped themselves with M1 (M50) and M1917 (M53) rifles. They could have come from that source.