Hi Robbo,
My husband inherited loads of just about everything recently from his parents who inherited from an uncle who was a manic collector of mainly studio pottery but also glass. I've been on a steep learning curve since October. A lot of the glass is Whitefriars but I came across these pieces of Kaj Franck and reading your conversation with Martyn K I now wonder whether some of the small shot glasses are actually KF rather than WF. I've got quite a few which are vaguely streaky iridescent, whose those might be I have no idea. I'll try and find time to put some on here in batches.
Chris