This Airtruk is VH-BPR, visiting Hoxton Park in August 1984. In April 1986 the aircraft was substantially damaged when it encountered severe turbulence on takeoff in Victoria, stalled and force-landed. I believe the pilot fortunately escaped with only minor injuries.
The next two are of T-300 Skyfarmer VH-BOU, taking part in the first Australian Aerial Agriculture Championship at Hoxton Park, May 19th – 20th, 1984. This was Brendan Kelly of Leongatha, Victoria, winning the fire bombing competition. (Thanks to Arthur R. and Australian Flying magazine for details).