The car driven by Peter Weston (Donald Sinden) was a 1928 Lagonda two-litre low chassis tourer, registration "PK 9201". It was one of four used by the Fox and Nicholl racing team in the 1929 season, the others being "PK 9202", "PK 9203", and "PK 9204".
Donald Sinden, Jeannie Carson and Roland Culver would appear together three years later in Mad Little Island (1958).
Vanessa's light blue car is a 1955 Cadillac Series 62 convertible. In excellent condition in 2020 this car could be worth $100,000 or more, depending on its engine.