I had assumed that this was Czech, and would be an easy find for factory/designer... Chřibská, probably... Hospodka, perhaps... it'll be in a book somewhere... or online...
But I'm stumped.
It's 13cm tall, 19cm wide, moulded foot, polished base, hotworked opalescent rim, and a lovely grid of lines of teeny-tiny bubbles that terminate in much bigger bubbles.
Any pointers in the right direction gratefully received.