Define "a couple of hours". My friend had 3 hours and *just* made it, but he had to change terminals and he didn't have the benefit of elite status to help him through the check-in queues. Plus it was in August, shortly after that mess in the UK, and the Indians were doing extra-thorough "security" at the time.

I'm not sure if changing terminals will be an issue with QF to CX, but I know you have elite status to speed you along.