Many thanks to all contributors! I would have never found all that info myself, much appreciated. Flying Free, mine is in fact different in shape to your Kralik, top diameter is 7.5cm, bottom 8cm.
Anne, thank you for the link, I was surprised to see the price TBH

I looked on eBay before posting but didn't see that one as I was looking for ruby glass only.
I was hoping for it to be British but it's interesting to know more about it anyway
