The first Series 4 is up for auction in Dorset to-day. This car was MPH100L and was used for the Avon Tyre blow out test by Tony Crook. That fact means that part of the text about the car is clearly wrong as the road wheels are later Blenheim alloys and the car started life with the Avons.
"The Bristol is also fitted with alloy road wheels which are believed to be original to the motor car."
The text also says that this "was the prototype for the 603 when it was subsequently fitted with the later 5.9 litre V8 engine, which is still retained today." The engine was not fitted until 18 months after the launch of the 603 so could not be the prototype.
Vintage & Classic Car Auctions
Post auction I will update the sales price - estimate is a low £38-42,000.