Marwyn were the first manufacturer, in 1947, to launch a series of production cars which were sold complete for £450 or as a kit of parts. Both used JAP engines. The company was based in Bournemouth and later moved to Wareham. The prototype, fitted with a Triumph twin engine, made its first appearance at the Brighton Speed Trials in September 1947 and came third in class, driven by Sir Francis Samuelson. The car suffered from having, a less than rigid, ladder chassis and relatively high ground clearance. The early Marwyns were not very stable and "Binky" Hall was killed when his overturned while testing. Subsequently, the large motorcycle wheels were replaced by 15in wheels, lowering the centre of gravity.
Another customer was Lord Strathcarron, a wartime RAF pilot and later a regular speaker on motoring matters in the House of Lords. He was employed as a "works" driver for weekly wage of £9 for 1948 and 1949 in spite of also being thrown from the car during a roll. Don Truman saw the failings of the first car and made a series of modifications to his, eventually becoming the Bardon Turner. Other Marwyns were modified by their owners including the Messenger JAP, Marott, driven by Denis Flather, SMS driven by Jeff Sparrowe, BRS by Jack Raper and MHM Triumph of JB Moncrieff. One car was exported to South Africa for Ernest Gearing who made his debut in June 1948 in a hill climb at Parow Quarry then rolled the car in its first race, the van Riebeeck Trophy, in October. One car was apparently exported to Canada for Major Persse but nothing is know of its fate Around half a dozen cars of the original design, were produced in all.
BE Martin demonstrates the Marwyn's handling at Shelsley, September 1947
A revised, lowered, car with all new body by Gray of Emsworth (who were also responsible for much of the body for Jon Cobb's Railton land speed record car) and hydraulic brakes was produced for 1949 but Cooper and others had raised the bar by then and limited successes were achieved. When the Marwyn company folded, it was taken over by Cyril Kieft who modified the design to create his own production car.