Harry Pratt designed and built his own car in the 1950's called the Drome Special.
That's it!
Apparently he built it to publicise his Drome Garage which was in Hulme, Manchester.
It was a 3-seater and used a fully balanced and blueprinted 6 cylinder Vauxhall engine. It had a birdcage-style frame and a hand-rolled aluminium body, and I believe it dated from 1950.
Here is the unmolested puzzle picture together with another photo: