As I'm currently in Melbourne, I've discovered this one in person!
There's a small exhibition at Melbourne Museum about the work of Phillip Zmood, Holden's chief designer for a long period. This is one of his designs, and a very interesting project.
This won the 1963 Institute of British Carriage & Automobile Manufacturers design award, and was intended to have a 1.0-litre rotary engine mounted centrally. Zmood designed it while studying industrial design at RMIT.
And its name? It's called the Gannet 1000.
PS I'm back home next month and will get back on the Autopuzzles case - and will post some pics of the Zmood exhibition