QED
(BBC documentary series, 1982-99)
Episode 4.03: The Future is Further Away Than You Think
Shown in 1983, this show was loosely about George Orwell's book '1984'. The affable Professor Heinz Wolff takes a bus back to 1948 (when the book was written) to see what changes have affected the 'man in the street' in the interim. The bus in question is London Transport STL441 (AXM693), new in 1934, provided by Cobham Bus Museum, and it's partly shot in black and white:
“There were several film clips (so lots of London bus types shown) used as if he was looking out of the window of the bus.” (thanks Bob Wingrove)
Glimpsed is a 1983 view of AEC Routemaster RML2542 (JJD542D):
“He later went to Northolt Airport (as a middle class person) and there was a clip showing a BOAC Commer Commando deck and a half Park Royal body.” (thanks again Bob Wingrove)
The star of the show is STL441:

Episode 10.07: John's Not Mad
Influential 1989 documentary about a Scottish teenager with Tourette's Syndrome, has a glimpse of a Leyland-National of Northern Scottish: