Post Costin and now based in Luton, Dennis and Peter Adams took Costin's chassis design with intention of it being put into poduction. The chassis was subcontracted to Sawbridgeworth, the company which assembled Mosquitoes in World War II. It was made 6" wider, and a full width one piece windscreen was introduced. The redesigned, notably sleeker bodywork, was fitted to the existing wooden chassis unit.

Introduced in November 1961, the Gullwing had a price tag of £830 which included all the parts needed to build one. 13 cars in all were produced.

In 1962 a Gullwing driven by John Hine and Richard Prior entered the Le Mans 24Hrs. The car was timed at 129mph on the Mulsanne straight, but unfortunately retired in the eighth hour with a failed camshaft. 

Together, Steve Miniprio, Grahame John and David Rees won over 40 races and broke 7 lap records in the Autosport 1000cc GT Championship between 1961 and 1962,- prompting Autosport to describe the Gullwing as " a formidable racing car ".