Best operator for the barrier reef is Mike Ball (scuba diving hall of fame alongside jacques cousteau) and the Best rate is thru Abyss scuba in Sydney (Padi best dive shop in the world 1st 2014 ) 61 2 95839662 or their website.They have a dive coming up with humbacks and the the usual stuff ,osprey reef and the cod hole of course.If you are ever in Sydney there are plenty of good diving spots all divemaster led and free
regards Peter b