Hi
Some comments on sites around Northern NSW and Southern Qld.
Juilian Rocks - Byron Bay is a great dive I would go with Blue Bay they run a bigger boat than Sundive/Byron Bay Dive centre, and you stay out for a double dive.
Welcome to Blue Bay Divers - Byron Bay's Most Comfortable Dive and Snorkel Boat Very relaxed professional operation (and I do no and have not used Sundive and Byron Bay dive centre)
Given the time of year you may see may there may be leopard sharks, mata rays... As said above Byron is very busy but a fun place Sundive and Byron Bay dive centre both have dive hostels some may accommodate and dive, their hostels are a short walk to the beach.
Flat Rock and Manta Bommie - Point Lookout Stradbroke Island (off Brisbane)
Manta Lodge and Scuba Centre : Stradbroke Island :: Learn to Dive - Online Open Water Course
Given the time of year you should see Mana Rays of Manta Bommie and other bigger fish of Flat Rock. Stradbroke Island is a great place to visit, great beaches and a nice 'pub' looking out to the ocean top for an afternoon beer!
Flinders Reef - off Brisbane there are a number of local operators that dive here (I haven't used than as I have my own boat for this dive) typically on weekends. Go Dive run Fridays
Scuba Dive Brisbane | Go Dive Brisbane | Learn To Scuba Dive | PADI Dive Shop and are a good shop. Go Dive may also run to some more remote sites that are not dived a lot.
https://www.google.com.au/search?q=f...ef+moreton+bay
Should see good coral, lots of fish and turtles.
Cherubs/Henderson/China Wall off the east side of Moreton Island. These are great dives 20-30m rocky reefs likely interesting topography. Probably better in winter with Grey Nurse and whales. Limited commercial diving as most operators do not go here. Go Dive may run a trip if conditions are right.
South West Rocks is a spectacular dive Fish Rock Cave
Fish Rock Cave - Dive Fish Rock with the South West Rocks Dive Centre Australia.
Probably see Gray Nurse possible hammer head sharks. South west Rocks Dive centre have a hostel. Diving is quite weather constrained so you could need a few days stop to get out. Some great beaches in the area. and a nice lighthouse at Smoky Cape, you can stay in the light house cottages, its a great stop to stay
At Sunshine Coast (Mooloolaba) just north of Brisbane, if you feel like a wreck dive (sunk navy ship), on the ex-HMAS Brisbane. I have dived with Sun Reef a few times they were good
http://www.sunreef.com.au/dive-the-e...ne-wreck-dive/ there is also
http://scubaworld.com.au/dive-sites/dive-hmas-brisbane/ also a good operator.
Coral can be found at Heron island. There is a resort and research station on the island. There is accommodation on the island.
http://diveadventures.com.au/pages/d...alia/heron.htm. I have dived this reef system but only from a 70foot yacht that no longer operates in the area.
Lady Elliot island will also get you on the GBR. I have friends who camp on the island on alternate Christmases. They take all the dive gear and compressor! But there is a resort
Diving on Lady Elliot Island | Lady Elliot Island Eco Resort Great Barrier Reef