By early July 1942 work was well behind schedule and costs had risen to £983,000. Shortly before that date, the Rover car company was selected as the user of the factory. Rover were at the time manufacturing engines for the Bristol Aeroplane Company. It was also intended to supply components to Rover's main shadow factories at Acocks Green and Solihull, to supply spare parts, and to act as a backup facility if either of the main shadow factories was damaged by enemy action. The cost to complete was estimated at a further £184,000; Rover’s requirements included acid-resistant floors and specially painted walls in production areas.