I was on that flight with my wife so let me inform you that after a 20 hour delay QF 10 did not take off at 8:30 but 9:40 so a further over hour delay making another hour in the aircraft. Yes we were business class. I personally found the cabin crew very friendly and helpful during the 17 hour flight
My wife had discussions with the cabin crew who told her the initial problem was a major fault in the air conditioning but that then blew the pilot rostering, resulting in a substantial delay getting the four pilots necessary for the flight.
Now in Oz many people tell me that Qantas suffers many long delays and cancellations.