They can then check the wires (because, as you know, there have been claims that the wiring may have been misconnected) and also the power output of the unit in relation to both the heated water and the steam.
The shells of the cars are made at Mr Collier's other factory in Beccles and transferred to a unit on an industrial estate at Acton where the engines are fitted along with the wiring and interiors before they are painted.