The old "Argus Tuft" callsign for RAAF
 

Need some help to settle a discussion - probably will help for RAAF pilots circa 70's & 80's to chime in.

When I was younger and flying gliders for the AIRTC (RAAF Cadets in those days) we used to monitor ATC to help with our radio calls. On several occasions, RAAF aircrew would use the callsign "Argus Tuft" when flying in to civilian airspace/landing at commercial airports.
They were also transcribed by Bob Bell (On the Airbands) in the Australian Aviation magazine late 80's

Can anyone enlighten please? (I know the reason, just want to hear if this was correct)

I thought that this was Australian RT for "Negative".