Just a trivia aside, but did the Viking and Varsity still have the geodetic internal and wing structure of the Wellington, just with a metal instead of canvas skin, or was the structure completely redesigned with the change of outer skin ?
The Valetta and Varsity had conventional frame-and-stringer fuselages.
I believe that Farnborough were still running a Varsity (a further-tweaked Viking, for military service again) into the early 1990s.
Hence my comment above about the Varsity outliving the Viking by 24 years (1968+22=1992).
Final Varsity flight (Farnborough to Cosford museum 27th July 1992):
