Unfortunately, like a lot of stuff, they're not available in the UK
Have you seen these plastic plectrums available from World of Ukes?
Unfortunately, like a lot of stuff, they're not available in the UK
These are fun but make lousy picks. I haven't found any material that it'll punch that works well. The punche picks are often sharp or ragged and need some filing and shaping before they're usable.You can buy a thing called a "pick punch" to make your own picks out of various materials.
I've tried all kinds of picks over the years, and ... lately I enjoy the green Jazz pick from Dunlop (Tortex Jazz, it's probably around 0.80mm). The Jazz picks are smaller, which I found works well for me, for now...