I agree that Richard Guider bought a March 782-chassis from the Toleman team in 1979 and built up the Marguey CA80 CanAm (later called CA82) with Hart-engine. He raced the car by himself, respectively Bertil Roos sat behind the steering wheel.
The bodywork came from another CanAm-car, named after the bodywork's designer! His name is the last brick to complete this puzzle....