Elfin is a australian 7 replica maker
Caterham has several dealers throughout australia
Westfeild cars has several dealers throughout australia.. Westfield has a car that can accept Windsor V8 or smaller/simular.
I seriously looked into getting one of these, unfortunately due to my size it wasn't possible (even with the larger 7s). Also the 7 shape is totally unaerodynamic, and even if you were the right size, a fairly unforgiving place to be.