UK (NATS) conducts annual NDB monitoring that is compliant to the UK CAA requirements for GBP500 or $800 Aussie.
I find this hard to believe.
The 12 month flight inspection requirements are driven by ICAO Annex 10/Doc 8071, not Airservices Australia "gold plating" the process.
Maybe you could get a service that monitors when the signal goes down for $800, but a flight inspection capable aircraft and crew? No way.