When these came out of the box a few weeks ago, I didn't really give them much of a look, and mentally labelled them "moulded, bohemian, mass-produced, for boot sale".
As I have been doing such a lot of research on other pieces, I started to see similar pieces that were a little more interesting than my original thoughts, so I have had a closer look.
There are very slight differences, consistent with blown and cut pieces. The bases have very fine striations under magnification, and are very, very slightly concave. Those fine striations are also apparent in the cutting.
At 8.25cm rim dia. x 6.25cm high, they are an odd size for anything I can think of. Too small for wine rinsers, would be OK for a finger bowl for me, but probably not for most people, too small diameter for dessert bowls.
I was starting to wonder if they might be VSL, then I saw some pieces attributed to England. So I decided to put them here and try and get some help.