Off the top of my head, I know Wayne Filan visited london at this time. He was mostly based in the states, set up the hot glass facilities in Philadelphia College of Art in '68, with William Bernstein and Dan Dailey. (info from "American Studio Glass, p.59, column 2. by Martha Drexler Lynn).
I've a friend who was a student of Bill Bernstein's, so he contacted Bill to ask if he had any knowledge of what happened to Wayne after that, but sadly he doesn't, he was just able to confirm the visit to London. I haven't contacted Dan Dailey yet, to see if he has any idea.
Some "Platinum Lustre" pieces have appeared on ebay, of a later date than the vase I have (London, '71), they're quite different to my London one, which is MUCH more Sam Hermany.