David don't think the money was important to him as with a lot of artists, was more about producing work that he was proud of & others liked.
I'm further North than you lol & although there may not be a coffee shop on every street there are a few about if you look. Normally high street sort of locations where you get a high volume of people passing through.
I wouldn't be looking at places that sell mass produced art either, different sort of customer from what you want entirely. Plus they would probably be looking to buy direct from you really cheaply so they could mark up to make a big profit rather than sell on a commission basis.
I do like the idea of sets that has been mentioned which would encourage people to buy more than one piece. If you produced say 3 or 4 pieces with a common theme or something linking them like say a sitting woman, same sitting pregnant woman & same sitting woman with child.
I wouldn't make them all as sets as not everyone will want that sort of thing but if you had a selection it might help.