Some answers, I hope!
I was posted to ARDU 1970 to 1974 as an armament fitter. During 1972 I went to Avalon daily with the rest of the ground crew, we operated 2 Mirages from there, A3-2, A3-76 but sometimes a dual would be used as a chase and photographic a/c.
We [ARDU] were engaged in flight and carriage trials on new weapon systems, during my time the biggy was Test schedule 1602 RPK10 fuel tank /bomb carrier. Also T/S 1624 high drag bomb tails, T/S 1632 Karinga [bomblets]
It was in 1972 that Sqn Ldr Richardson ejected just north of Geelong road in a factory a/c, not an ARDU one.
1972 was the year we trucked an a/c up the highway to Laverton, boy was that a slow trip. I was in the VW combi behind the semi, we had cars stacked up behind us for miles. The Air Force didnt get much good publicity that day, at least from what was shouted at us as the cars finally struggled past us.