Body buck for the A98?
Exactly, yes.
It's the original A98 under construction in 1963. This was of course the car AC tested on the new M1 motorway when they were preparing it for entry in the 1964 Le Mans 24 hour race, the public, media and politicians taking great exception to cars being driven at over 180 mph on public roads; have they no soul?! It is said that led directly to the 70 mph limit on our motorways, from which we have never recovered..
Here's a picture of the completed car, which underwent numerous changes before its actual Le Mans appearance, and one of the car recently restored, which I believe might have been puzzled here before but I can't find it: