I wonder whether any European Ebid seed sellers have stocks of Wing Beans, sometimes called Asparagus Peas.
They are pea/beans with four "wings".
Available on Ebid Australia, but australian seeds don't always pass through customs.
You can eat the red flowers, the beans are yummy, the leaves taste like spinach, and although they are tropical in origin, they grow easily in London.
The last lot I got in a shop in Kowloon, Hong Kong a few years ago, and it is a bit far to go for a packet of seeds . . .