(1955, Kent Taylor, Petula Clark)

Brief footage of Victoria Bus Station:

….followed by Victoria Coach Station:

Inside we glimpse a 1952 Southdown Leyland Royal Tiger/East Lancs, alongside what proves to be W S Hunt B3 (KPA836), a Bedford OWB:

KPA836 is a 1943 Bedford OWB rebuilt in 1951 with a postwar Duple body. It appeared in its original guise in the 1946 movie School for Secrets.
Behind the Royal Tiger is a second Southdown Royal Tiger, Duple Ambassador-bodied:

As KPA836 leaves Victoria Coach Station, we also see a Maidstone and District AEC Regal III, registration unclear, but KKK8x5 can be made out:

In front of it is another Maidstone and District vehicle, a Beadle-Leyland integral:

More clearly seen is a Black and White Motorways Guy Arab LUF/Duple:

…and there's a Thames Valley lowbridge Bristol KSW/Eastern Coachworks:

The coach is integral to the plot, and interior scenes are mixed with the exterior shots: