Thanks for the reply. I had attempted to search through that site, although my German is "nicht" good! I could see similarities in the design, the only problem was that I could say the same about some English designed glasses.
I don't know if it will help, but alongside buying a set of these glasses I bought the decanter, tray and tiny glasses (hopefully!) shown in the photographs below. Assuming they are all by the same glassworks, do they jog any memories/points of reference?
The decanter is approx. 9 inches tall (with a hollow stopper) the tray approx. 10.5 inches wide (with a polished out pontil mark) and the tiny glasses appox. 2.5 inches tall.