His name was Gerry Bath, and the car was called Pegasus. It was built from the basis of a Triumph Super Seven chassis, with running gear from Ford and Austin parts, and powered by a Ford 10hp engine. He originally intended to fit a Raleigh V-twin motor! It competed in hillclimbs, sprints and races during 1951/52. The article on the internet does not state exactly where the photo was taken , but I think it was Naish hillclimb - the road looks too narrow to be a racing circuit.
(I found this whilst looking for something completely different- it happens to us all the time!)