I can't quite believe it but I just stumbled onto this whilst looking for something totally different....
This is the Grayford Special, originally built in the very early 1950s by Jem Marsh. It was originally built to compete in 750mcc events based around Austin 7 mechanics. The car was sold in 1956 and went through a number of modifications and owners. The picture shows the car in the mid 1960s when owned by Geoffrey Gook of Southampton, who replaced the cars 1172 Ford engine with a Coventry Climax unit and owned the car until 1983. It still survives today, in a fairly similar configuration after having a number of more recent mods reversed and returning it to something more like a typical '60s 'clubman racer'