Hi William, thanks for writing in about your wife's antique wedding band. Heirloom antique wedding bands, are so special, plus another big advantage in secondary pieces, they leave no negative impact on the environment, they don't cost the earth!
More info is needed, for instance, do you know if your wife's great grandmother migrated to Canada? The main problem being, there are a number of maker's with J.A initials on both sides of the pond, so we need to narrow down the field.
It's also not uncommon to see hallmarks with jewelry marks that resemble UK marks - these types of marks are known as "pseudo-marks", however there's nothing inferior with pseudo marks, jewelers & artists often emulate, however many people confuse these marks with UK marks, and without seeing the mark, it's difficult to say.
The number "9" would be the gold purity mark, and this particular caratage has served this antique ring well, as 9 carat gold is the strongest and the most hard-wearing.