Ok, that was a massive ordeal. I tried to get 4 Red Zone tickets for Melbourne, but there was constantly an error when submitting the request, not anything saying they were out of tickets. I called them and they were having similar problems trying to book it in their own systems.
I was able to order 2 x RedZone tickets fine across the internet and once it was in the system they were able to add the additional 2 tickets to the order. Very strange as there was nothing written to limit the amount of Red Zone tickets in the terms and conditions, it simply said 4 tickets per order.
Either way, I've got them now. Bring on DECEMBER!!! Big month ahead as I have 10th row seats for Muse on the 12th and now Red Zone tickets for U2 on the 1st. Shame they are all midweek concerts, I may need to take some time off work