Thanks Kevin, I was nearly hearing tumbleweed there! My thought it could be continental is encouraged by your not having seen it. Secondly, a bit of google detection and checking a GMB thread, yielded a suggestion that, of all places, Holmegaard appears to have used HG7 to denote a design from 1977 and the lettering style matches some examples too. .... rather than a P.L match I will now look for S.W. as a designer possibility.... glass is an unexpected thing at times.
Robert (bOBA)