I remember seeing his first car run at Santa Pod. The one in the vid was the second, as the first caught fire. It had GM auto gearbox as John Dodd did repairs on auto gearboxes. The original did look quite a bit like a roller
(well maybe not)
When Fibre Glass Repairs was building it they bought a new RR radiator and lowered it by a couple of inches as it was too tall for the bodywork. I remember reading that on one trip he did 1000 miles in ten hours including going through 3 sets of Border crossings.