one11:
You beat me to it. I have my copy of Civil Aircraft Markings 1953 ready to sent the advert you posted! However, I can add that the price had gone down by then. In 1952 it was 1 pound for a bike and 12 for a car. It hit an all time low of 4/6 for a bike in 1954.
My only experience of flying the car was Lydd-Le Touquet December 1967 in 170/32 G-ANWM, and return in January 1968 in G-APAU.
Laurence