I haven't been able to find anything specific in my research. My best estimate is around mid-century 1950/60's.
I have found this:
Hammersley China Company. Renowned for their tasteful hand painting. Colors were bold and beautiful and never ceased to amaze the buyer. Hammersley China Company quickly became a favorite amongst Canadians from the late Thirties to the early 1960s. It was associated with quality and is avidly collected amongst the more affluent Canadian. If you wanted color for the china cabinet, this was it.
Hi there - I'm still trying to understand why it's more expensive to ship an item between two addresses in Ontario than it is to ship to the furthest south west corner of the US. It baffles me. Anyhow, it looks like shipping costs would be around $10-12. Thanks for looking!