I have seen this post sitting here since yesterday with no replies. I know there are several general areas for bait out to the Barwons - 8mile, 10mile, 18mile, 21mile etc. Should be some general area marks for these floating around somewhere on the web. Try SCGFC website.
Otherthan that, the topic of bait grounds off Mooloolaba comes up every few months on ausfish and it is worth doing a search to find past threads.
Jeremy