Don't know but you can be sure that QF will be a lot more expensive than its competitors. Shop around.
As it happens this one isn't coming out of our budget so price -- within reason and notwithstanding a travel policy that puts us in whY (grr) -- isn't the primary concern. The QF flights are actually cheaper for the particular dates we need vs JAL (and these are the only direct options ex-MEL as far as I can tell; this is a short trip so connecting is not really an option). Anyway we have now booked onto QF79/80. Fingers crossed.