This is David Davies' beautiful and very rare 1931 Light Six Saloon.  As far as we know this is the sole surviving example of this model - even this one didn't appear in the Millennium Project listing.

Originally called the Senior Six, it has a 1752cc side-valve engine which was rated at
15.7 hp. With a four main-bearing crankshaft fitted with a vibration damper, the car is very smooth to drive. It is also very well appointed, with real leather upholstery and patent flush-fitting sliding roof.