It's not entirely unheard of for shows to leave such minimal traces. Often, distribution deals don't guarantee long-term preservation. Especially for a series that got dubbed across so many regions, physical copies might've just vanished over time. Plus, if digital wasn't a priority back then, finding full episodes could be …

I work in archiving, so I might be able to help a bit. The BBC is notoriously difficult when it comes to accessing unaired pilots like this. They might not even know exactly where it is or its condition. Best long shot is to network with BBC staffers past and …