I was in Kingston SE for a few days around January 2013 and parked up at a designated free camp spot near the jetty.
There were toilets with cold showers.
Coin operated BBQ, and benches on a beautiful grassed area.
It was a very short walk to the shops.
The sign at the time said self contained only, although the toilets were never closed.
From memory the water taps were marked as non portable.
After dark the area filled up with backpackers, and tents, who left very early in the mornings.
There was a very nice cycle/walkway which went for a fair way around the bay.