Although Esso had its own CASA approved check and training section, it never held an AOC, and they fought tooth and nail against it when CASA tried to make them hold an AOC.
AAAAHHH!!! That brings back some memories (nightmares) of the early 2000s, when a then Assistant Director of CASA decided there was going to be a "Private Operations AOC", with all the trappings of a full on AOC, plus a few wrinkles of his own.
"Traditional" Private Operations was to be limited to "the immediate family of the owner of the aircraft" ---- which immediately precluded a PPL hiring an aircraft, unless it was operated by a holder of a said "POAOC".
It was intended to bring ALL corporate operations, and most traditional private operations in Australia under an AOC. Also Limited Cat. C.of A aircraft.
The ABAA were smart enough to see off the proposal, not so AWAL.
In a wonderful example of gross over-regulation of non-existent problems (about 15 years of satisfactory and safe operations without it) Part 132 came about, no "safety" problem to mitigate, no benefit/cost analysis, it happened. But all the usual downsides, cost, complexity, and in this case, a few category unique problems.
A not so isolated example of how hard it is to kill a bad idea in CASA, once it takes root.
Tootle pip!!