Whilst there have been mentions of this car elsewhere I thought it might be worth starting a new thread so all the information we have could be collected in the one place. The proper/full name is the Elfin Type 100 chassis M6548 with the V6 Clisby F1 engine.
To start things off, here is an article from the short-lived Australian Weekly Autonews February 1965 (with thanks to Cooper997).