Der Goldene Schlussel (1966)

A colour cutdown version of The Diadem a 13 minute black and white short, where Diana Rigg gets to wander around in the slightest of crime drama's made for the 8mm market, by a German producer.
This version has Diana do much of the same things as the Black and white version, just omitting some of the chasing around, a fight scene or two and includes a different reveal ending. Neither are essential viewing, unless you have to watch everything Diana Rigg has done!

the diadem (1966)

A short produced in two versions, the longer black and white silent and the even shorter colour version. Essentially a mini-mystery starring Diana Rigg as a psuedo Emma Peel character who gets involved in a treasure hunt. She flies a plane, swims with dolphins, stops for a couple of glasses of champagne, and slaps around various men before finally discovering a diamond tiara.
An amateurish curio nothing more, which makes you ask the question, why did Diana Rigg get involved in this?