I asked the question on the VSCC forum as the car was in the Pom this year. The answer, so far as it went was
The Jag was rebodied by a man called Tindal a long time ago
The man who gave the answer knows Mr Tindal's son, so I'll see what that leads to.
I guess that Tindal knew the E type and fancied having a car that shape, but with some changes, and went ahead and built one from the old XK140 he happened to have.
Lister Knobbly refers to the body shape vis a vis the Costin-bodied later ones. Their wheels were, as stated, Dunlop knock-ons like those of the D type Jaguar. Knobbly wheels were on things like Cooper and Lotus, but I can't recall anyone calling them "knobbly" at the time.
Oh, and the first Lister Jaguar was built on a Lister-Bristol/Maserati frame.