Shipping? No idea, but a ball-park figure maybe 800 quid for a Ro-Ro service?
It's a piece of cake getting it out of the UK, but how much are the government going to hump you on landing charges / taxes / etc?
Have a butchers at
THIS PDF attachment I found with Google and look at all the extras...
Start here:
http://www.customs.gov.au/site/page4371.asp
Then check what you might need to do to the car to get a safety cert in your state. Some items like seatbelts might need to be Aussie approved one???
I've only shipped cars from UK to Ireland, but there's three things always to consider wherever you go:
1) Cost of getting it there and clearing it: shipping costs (to port / on boat / from port at the other end), customs, all local taxes, etc.
2) Cost of running it there: annual circulation charges (road tax), insurances, fuel consumption, parts, etc.