Thank you for the responses.

The point is that I want both seats as I want my son to have a seat (although he will sit in PE and one of the adults will move to Business if the upgrades don't come through).

I am willing to forgo 60,000 points for the privelege (plus taxes) - we were the ones that made the award booking for the adult passenger. Plus the PE fare we have already paid

Hence, the question is focused on why Qantas shouldn't allow us to effectively purchase two seats on the same plane. Commercially I just can't understand why they wouldn't allow it if they are being paid for it.