I had a close look at the pic with the eBay zoom function, it might be called "Goolwa" but the beach is different than that, Goolwa beach has smallish sand dunes covered by a spiky grass rather than rolling hills in the background also the wash away near the yacht doesn't happen on the top of the beach as there is little or no run off from the dunes Goolwa beach is straight or has only a very slightish turn on it.
The beach is most like Aldinga / Sellicks beach with the hills behind and the wash-aways and the turn of the coast or a mix of both with a stylized land yacht on it.
Never the less a VERY nice picture....
eBay picture
Goolwa Beach
Aldinga - Selicks Beach
Here is a magazine article published many years ago about a trip along the Coorong Beach, just the other side of the River Murray mouth from Goolwa beach
www.seabreeze.com.au/forums/Land-Yacht-Sailing/Events-Competitions/Beach-Blast/