Are you as I am 'of a certain age' and did you have Mint in your garden back in the 1960s or earlier? Our patch of Mint was there for years, and provided lots of leaves to add to boiled Potatoes. Eventually it got yellow patches on the leaves, a virus perhaps, but it still grew away year after year. I can't remember what eventually happened to it but, nowadays whenever I go to a garden centre, I sniff at the many types of Mint on display, but none of them seem to be the same. I'm not keen on the Spearmint type, and the memory of the smell of our 1960s Mint has probably become faded and distorted over the years, so it's anyone's guess as to what variety it could have been.