Yes. It was there . I just had to double check. They also had a Napier triple bank engine on display.
Brilliant! It's an absolutely fabulous car. Took nine months to go from blank sheet of paper to finished car in the early 1930s.
Ah, and the engine would be a Napier Lion of some description. There's an XI-A series in the Railton itself - the original engine, but a lot of other cars of the era (mainly LSR cars) used the many variants of the VII series, which were engines designed specifically for racing. OK, when I say racing, we're talking Schneider Trophy here, and they just got appropriated into cars and boats.
The Lion is the best example of a successful W-12 configuration engine. They tried them in F1 in the late 80s / early 90s, but without much luck. The Lion's strength was its relative simplicity, as everything could run off a single crankshaft thanks to each bank of cylinders being at 60 degrees to each other. Trouble is, that's quite a wide configuration - in the F1 cars, they narrowed the angle between the banks to be able to fit the engine to the car, but that meant using two crankshafts. Which meant a lot of mechanical and reliability issues. Something which the Lion never really had.