It just occurred to me that I remember a UK TV appearance of an M400, many many years ago, which was NOT associated with any band, Whistle Test, Top of the Pops etc.
Late afternoon, one Saturday in August 1977 (I can tell you it was the day when Elvis died as it was reported on the news immmediately after the programme!)
Switched on the TV just in time to see the end credits rolling.. over a closeup of someone playing an M400!
I learned a few days later from a mate that the Mellotron had been featured, described and demonstrated on said program, which appears to have been a sort of early prototype 'Rock School' showcasing instruments and technique for anyone interested. And I missed it. Bugger!
I know it's HIGHLY unlikely, but does anyone have any recollections to add? It has bugged me ever since!
Best,
Paul Marshall