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I saw Dave Garrnet use this on the hills in the late 70's, it was crashed in Jersey in 78 and never made it to Gursney, but made it to Val Des Terres the following year.
He was using it in 77 as well, he set the class hill record that year that remained unbroken for a couple of seasons
Not sure what type it is as the front does not seem to match any other type.