Just to keep Martin Happy, here is a picture during the build.
This is a car from the film, no plans, just some photos, the car still exists albeit in a different colour, it is now green. There are quite a lot of different Alvis 12/60 Sports around, this is a 1931 version,
This is my best guess, I think it may be a bit wide, but it is too late now.
The car has been rebodied in 1950's.
Alvis used different coach builders, so they are all a bit different.
This was by Carbodies?
I bought some new Milliput - turquoise - very trendy. It sets better than my old stuff.
Look at the rear end.