From a logistical side of things, there is not car carrier service that will take a car from GB to AUS.
The only way would be in a container. probably 20ft if you're going to go it alone or if you talked to a freight forwarder, they may have a 40ft conatiner they could put it in. 3 to a container would be about right and would make the cost less
Freight rates are about US$1200 for a container to come to aus plus unpacking and wharfage costs. looking at about 2.5-3g's depending on how much the forwarder will rip you.
from there its like any other import...customs, compliance etc
Would have to be a decent car to be worth it
hope that helps man