On my maps, the highest bits of dirt for miles around Goolwa are 1-2000' - hardly conducive to "standing waves".
Given the topography around Goolwa, I would (as a practising glider pilot) fully expect to see a myriad of standing waves in the area in the presence of 35-45kt winds.
Whether they would go all the way to the ground depends largely on the conditions of the day, but having spent some time messing with Tigerschmitts, I would agree that in the conditions, the best place for one would be in a hangar with the doors shut.
Certainly, my Auster would not be taken out in those conditions unless I had very good reason and it's a little more tolerant than the venerable barn door that is the DH82.
Also, the PLOD in question was qualified to make that comment.