Moreton Island

There are some spots on the eastern beach (north-east zone or maybe blue lagoon) that would fit a large group in - or you could at least be nearby. There's also northpoint campground - it's quite open and suitable for big groups (and would be near enough to completely empty in november) but I think there are some bollards so not sure about camper trailers.
I think there are some bigger open areas in the north-west zone but I don't know much about them. Seemed to be some big groups in there when we went past at easter.

We (2 adults + 2 kids) go every year around october november for a week. With two small children we prefer the quite waters of the western side.

We usually camp at the Comboyuro campground. It has a shower, toilets and about 50 sites spread over a kilometre. the camp site are open so ok for camper trailers. You can walk to bulwer from this campground and the ferry goes to Bulwer every Tuesday if you don't fance the drive from tangalooma. Cars are banned from driving on that beach (although that doesn't stop the idiots). At that time of the year we are the only campers there for most of the week. For a large group you could book 5 sites next to each other as there is going to be plenty of space.

Hopefully when we go this year I'll try and avoid your large group by seeing when and where you are camped in the booking
register.

all the best

R.

Jono, This Link may help you.

We have been going to Moreton on the January long weekend for a few years and stay in the Northwest camping zone. There are no showers or toilets but only a short drive down to other campsites or just bring your own.

Fantastic site right on the beach but set among trees and really beautiful sunsets. Areas are large enough for more than 20 campers, tents, etc.