Thanks. Yeah, I've checked out everything I can find by Hergiswil, Glarner, Oberglas, Ingrid, Georgshütte, Schott, Zwiesel etc, Zlatno and Czechs/Slovaks, and all the Scandis I can think of, but nothing yet.
It's particularly annoying that there's a bothery watchmaker that goes by the name of Glashütte.
[Hey, Anne, can we have a bashing-head-against-wall smiley, too?]