When not racing cars, Parkes worked as an automotive engineer, and whilst working for the Rootes Group was involved in the project which led to production of the Hillman Imp.
Ao non competir cos automóbiles, Parkes traballou como enxeñeiro automotriz, Mentres que traballaba para o grupo Rootes estaba implicado no proxecto que conduciu á produción de Hillman Imp.