I seem to have unwittingly started something here! As JDLee has pointed out, the Bertelli MPH is a civilised sports car, although it's very early days may hold some competition secrets. 6 MPH cars were built by Riley as pure competition cars, these were 2 seaters but very light weight and pointed tails etc. The 6 cylinder Riley engine was the basis of the ERA single seater racers,which were very successful and are all still racing today. About 15 MPH were built, they had Electron diffs.,15 inch Electron brakes drums and mine has a pre selector Electron gearbox. So the 'production' cars were basically the same chassis as the racers but with all the creature conforts of the day. They failed to sell because they were too expensive at £550. The Bertelli MPH appears to be the only one with a non standard body. The body was built by Aston Martin's coachbuilder, Enrico Bertelli, who was the brother of the owner of Aston Martin, A.C. Bertelli. I hope this info. is of some interest.