 According to John Heseltine (who restored the car for the film)  David Niven (I) (qv) couldnt master the idiosyncratic gearbox of  the Cord 810 and subsequently it was driven in bottom gear,  resulting in it overheating. The scene in the film showing the  steaming Cord was hastily rewritten to work around the problem. The  car had to be restored from nothing but a rusty collection of parts  in just six months to get it ready for filming.