Richard,
That is the Hispano Suiza/Wolseley Viper 18L engined car isn't it. I love these aero engined vintage cars. A friend of mine has built an RR Phantom II with a Meteor 27L V12 engine and had Rob Jolley make a body similar to the Napier Railton for it. The only thing I don't like is that he has used a GM400 auto box with it , after a step up intermediate box. It would have been better IMHO, if he had used an old non-synchro truck gearbox or even a W.O.Bentley D box (the 8L one).
Wilson