Well, I'm hardly an expert, but as there seems to be a little confusion here as to which car is which I'll add this:
The two cars in your puzzles are in fact different. This one is indeed prototype #2 as built by Williams & Pritchard. the car in puzzle 1119 is #1 which was built by Maurice Gomm.
There are some nice pictures of this 2nd car completed in colour but they seem to have vanished from the internet at the moment