I tried every code from every coupon site I could find, to no avail. Not even Groupon or RACQ give the option to buy annual passes! At this point, is it really worth it? With 15% cashback from CR and 15% local discount from Groupon, we must go at least 4x times in the year to be worth it (we're a 20 min drive from the zoo, so that's not unlikely).
I'm close by as well, but sadly even when Groupon deals come by they are only a few % away from full price.