But I think if the puzzle car is a Lister Jaguar it would certainly have been mentioned in the Classic Cars For Sale ad, don't you?
So I'll leave the Lister bit off the heading unless I see definitive proof otherwise!
We've proved several times over that it is a special-bodied XK140 and has no Lister connection. The Classic Cars For Sale ad is pretty rough stuff, but it makes no claims that it is anything other than a special. XK140 had a chassis, not a floor pan and I can't think what the "usual XK steel panels" that he replaced were, once it had a body like that.
I looked up David Hobbs' car in Paul Skilliter's Jaguar Sports Cars, but it gets only a very short reference in the text. However there is a five-photo set of the Oulton Park accident in which you can see it's TAC743 and then there's a photo of it as per this puzzle "rebodied by Dick Tindell for Freddie Owen"