This car is a regular competitor at hill-climb events, though it looks a bit different now, as it is painted silver, and has a different front grille and other changes.
It is entered in these events as a Grenfell Special, and is powered by a 3.9-litre Ford flathead V8 engine. It dates from 1948.
But here the confusion starts. It has been associated with Jack Granville Grenfell, the Brooklands-based tuning and supercharging expert, but I haven't found anything to convince me that that's correct. The black and white rear view of the car shown below appears on a web page with a brief biography of Jack Grenfell, but it's identified as his second 500-cc Special from the early 1950s, which is obviously wrong. That car was a single-seater racer, and looked quite different.
But that's all the information I have at the moment, and I'm not sure how accurate it is.