This is a copy and paste directly from the Qantas recruitment web page.
Residency
Australian citizen or Hold Australian Permanent Residency Status
Hold a current passport with unrestricted access to all Qantas ports of call with at least 12 months validity
Australian Birth Certificate, or
Valid Australian passport, or
Overseas passport with Australian Permanent Residency visa
UK citizens like everybody else have to apply for a visa to live and work in Australia. Probably the only exception is New Zealand.
BTW, it's QANTAS not quantas. Queensland and Northern Territory Aerial Services.
If you want to live and work in Australia, check out REX. A small Australian regional airline. They have been known to sponsor working visas for pilots. Might be good stepping stone to permanent residency in Australia.