Judge Death wrote:
If there was someone out there with a huge stash, what would stop them cutting out the middle man, as it were, and just making a deal with a DVD production company? Or are the episodes still effectively BBC copyright material (even though the BBC effectively destroyed all copies back in the day).
The episodes themselves are BBC copyright until 70 years after the end of the year in which the death occurs of the last to survive of the principal director, the authors of the screenplay and dialogue, and the composer of any music specially created for the film.*
The physical cans of film they're stored on are another matter.