Unfortunately this technique was very common in Germany and Czech glass. I've seen recently seen that Nachtmann for instance still offers this type of wine glasses (cut glass with coloured overlay) for sale (at very high prices per piece I might add, so they might even be still handmade that way).
I was hoping to pin this one down on the more 60s-70s style pattern and hopefully the label, or I wouldn't have bothered to post mine in a long time... If Dirk doesn't know it, I'm assuming it's one of the many, many lesser known glasworks, and I'll have to be content to put it down as German between 1945 and 1990 (luckily "West-Germany" at least gives it time window).
Thanks everyone for looking and thinking with me,
Astrid