Gee, I thought this one had been solved ages ago, I guess I should look over old Professional puzzles more closely. Anyway, after digging through my records, I found some notes from several months ago, which say that, after extensive Googling for modified '40's & '50's British Ford cars, I came across the photograph below.
I thought that the person in this photograph looked remarkably like the tall gent in the center of the puzzle photograph. So going to the very obscure site where this photograph is located, I discovered that the puzzle photograph was also located there, and, yes, the tall gent in both pictures is the same person, and the builder of the puzzle car. The caption on the puzzle car photograph reads in part: "The car was hand built by Ivor White who called all his cars Whitford specials."