All well dressed commuter/charter pilots wore that rig except that if it was far enough north or far enough west the tie around the neck was an optional extra attracting the ridicule of the locals.
The shorts were modelled, in length anyway, on the tight pants VFL players wore, or it seemed that way anyway.
From my re-collection TAA had the swept tail Queenairs in use in Tassie in RPT which later were deployed in Qld to replace the Drovers circa late 1960's.....rego TGA etc. TAA had their pilots on secondment and were responsible for licencing. I well remember a TAA F27 Captain who officially moonlighted as the Queenair check pilot for the RFDS.