Not knowing the legal side of Aviation internal and external applicants policy.
I know many large companies have an equal opportunity policy which allows all internal and external applicants the chance to be interviewed and you can not be discriminated against if you are in either category... That being said I and others have been offered the job and told "we have an obligation to seek external applicants still, stdby"
Assume it's no different in Qantas, on paper at least..