G'day Face,
I expect you have worked out that you get Aussie dollars very cheaply with your pounds these days.
If you do decide to train here, I absolutely recommend Bankstown Helicopters (at Sydney's prime GA airport).
http://www.bankstownhelicopters.com.au
I'm not sure whether you will be exempted our 10% GST, but by prepaying 10 hours at a time you should be paying A$300 (just over 100 pounds) plus GST per hour dual at a very professional school, flying very schmick Robbies.
Cheap living, great weather, one of worlds greatest cities, not overpopulated, cheery Aussies, culturally close enough. What more could you ask for??