Hi Kasper. Your first line says that dropping down to 500' was fine back in the early 90's - is the second line a reference to current restrictions?
Let me put it this way. If we're talking mid 80's here, could someone have flown there early in the morning, performed a quick circuit round the rock a few hundred feet above it, same again for Kata Tjuta, and gotten away with it as long as there was no other air traffic? Maybe it was legal back then, maybe not, I don't know. I could just wing it in the story, if you'll pardon the pun, but I'd like to be accurate if possible.
As for the touch and go, the only one I can find was very recent, in 2015. http://www.aero-news.net/index.cfm?do=main.textpost&id=1d3c5931-c2f2-40f6-b3e9-5787fce5bbc5#:~:text=Left Tire Marks On The,formerly known as Ayers Rock. I really don't know how anyone could manage it safely, because the top is heavily ridged - I climbed it long ago, well before the Anangu began asking people to respect their wishes and not make the climb. Last time I went there in 2011, with my American wife and kids, we just walked around the base.