I was wondering when did Thorn sell their Fiberglass Alpha 8 lanterns to WRTL. Same goes to GEC Z8600 (Series), GEC Z9454, GEC Z9554M, GEC Z8830 (series) and GEC Nighwatch.

My GUESS is the mid 1990s for all of the gec products, but into the 2000s for the Alpha 8.