‘Clapperboard: The Empire Strikes Back Special’:-
https://www.youtube.com/watch?v=bJRqkV1ATs0 - at the Neil Bowyer youtube channel. (A 1980 documentary. 26 mins)
The Blurb:-
"Originally broadcast in 1980, this edition of Clapperboard (a weekly film show hosted by Chris Kelly on the UK ITV network) was filmed during the Empire Strikes Back exhibition at Selfridges in London (a further exhibition was held at Harrods for Return Of The Jedi in 1983).
Interviewed on the programme are Anthony Daniels (C-3PO), David Prowse (Darth Vader) and Brian Johnson (Special Visual Effects)."