Not good... :(
Unknowingly put themselves into 'alternate law' and once gear was down (gravity extension due turning ADIRS 1 + 3 off), into 'direct law' by intentionally turning off the ADR part!
IMHO, the FO was clueless in what he had done/ was doing and the Captain of similar ilk. What was wrong with a radar vectored, raw data approach back into Sydney after reviewing the initial situation? That's right, they went into the wrong fault diagnosis and further compounded the situation! Airbus pilots I work with, understand what was initially done is wrong.
Great. Now 'Everyone can Fly!' The Air Asia accident in Indonesia wasn't that long ago and due to unknowingly putting themselves into a diabolical situation. The travelling public doesn't understand the gravity of what second rate Airlines can potentially do.
Why are pilot's paid better at some Airlines and not others? Answer is, that better paying Airlines expect their safety and training standards' to be upheld by their pilot's, thus maintaining their better reputations.
Anyone can have a bad day out? Even more so, if they do not understand the aircraft they are flying!