Just from the advertisement it looks quite good...
i have one Astra F 3dr but in diesel and its in Poland...so far i dont have any issues with the engine, which in your case does not apply as i believe Australia did not get the Astra F diesel
there are few little gremlins with the electrical system playing some little 'tricks' from time to time but nothing major...
honestly i cannot add anything more...i hope you get some replies from Australian owners. Good luck!