Update,

Been talking to Mark at MMC and the paint code stamped on the car plate is an internal paint code that only means something to the factory and the colour is not a Bentley colour but a Lotus colour and the code that Williams give the factory is an ICI colour code which still does not come up on any searches and the only Lotus code there is for Velvet Red is C163 so just ordered some of that.

Nothing is easy with a Morgan.