I think it's more likely that one BBC journalist and their friends hadn't heard of it, because they don't sell it in Waitrose. They can make a whole series of

I think it's more likely that one BBC journalist and their friends hadn't heard of it, because they don't sell it in Waitrose. They can make a whole series of articles, as they "discover" damsons, greengage, quince, mulberries, gooseberries, etc. (Between my parents, grandparents, and places like the car park at the back of my mum's office, we picked all of these in England.) There are plenty of results on British websites for medlar trees (for gardeners) and recipes for the fruit.