Bolwell is a racing car designer and maker of specialty racing vehicles such as the Bolwell Mk 4 - Mk 7 car kits. He worked with Lotus UK in 1966 and developed another Bolwell, Mk 8 in 1969. He later turned to composite materials design working with yachts, windmills and other applications. After 1980, he returned to racing cars with a Mk 10 machine released in 2008.