Mate, if you ask the council you are most likely asking for refusal, lengthy paperwork and a non event waiting to happen. If the council can stop you parking your Cub in your paddock, they can also stop you driving your car there, riding your four-wheeler there or operating your tractor there.
There are far too many Australians already that think they need permission for everything, don't join them. Remember your UK tenant, "A mans home is his castle". Asking does nothing more than give more imagined power to bureaucrats.
For my airstrip, I simply smoothed a paddock and started using it and my aircraft needs a few more metres than the average Cub.
Go for it without asking, my feeling is you will have no regrets.