Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 132,834 pages of information and 210,602 images on early companies, their products and the people who designed and built them.
Post-WWI: Facing bankruptcy in the existing business of Grahame-White Aviation Co, Claude Grahame-White diversified into furniture and car manufacture, presumably as Grahame-White Co. He discovered a lucrative business in refurbishing war-surplus Rolls-Royce Silver Ghost chassis.
1919 "The simplest of all new four-wheelers, the Grahame-White Buckboard, may be said to occupy the same position in the "car" world as does the scooter in the sphere of motor cycles. It is a small vehicle consisting of little, more than a motor-driven rear axle and a front axle connected by a platform of wood without springs, the flexible qualities of the wood being considered sufficient to insulate the passengers from the worst road shocks. A 3 h.p. two-stroke engine provides the power, the transmission being by chain to a countershaft gear box at the rear of the platform, thence by belt to the axle. Incidentally, this Buckboard is a development of a little machine which has been marketed in America for some time; it is known as the Smith Flyer, and differs in so far that the power is provided by an Auto-wheel. The price is 95 guineas." 
1920 November. Exhibited at the Motor Car Show at Olympia and the White City with a lightweight car seating two and weighing 5cwt.