The company was officially formed at Stag Lane in February 1944 and later moved into a factory leased by the government in 1946 at Leavesden, which had earlier been a site for Handley Page Halifax production.
It is reported that the engine was then displayed in the showroom of the de Havilland Engine Company at Leavesden.
After completing the Harry Potter film series, McMillan and Craig collaborated on the designs for the Harry Potter theme park in Orlando, Florida, and 'The Magical World of Harry Potter', which Warner built at its studios at Leavesden, Hertfordshire, which opened in April 2012.