Thank you Ivo, funnily enough I'd found this page last night as well, having been trying to find out about the Nachtmann range called Crystal Creatures (I couldn't find the creatures though!).
The glasses I have are not like these at all. They came in a box with slots for them to fit into, the box was printed all over Astra Glass (I can't find the box just now but I was sure I'd kept it somewhere!), and the glasses are small liqueur sized ones - each is a different colour bowl on a clear stem, but the glass is coloured irridescent/pearly... there's probably a technical word for the type of glass but I don't know what it is. It doesn't seem to be a surface finish like many of the modern pearly finishes I've seen which eventually wears off.