I can only find one article to suggest that a Cadaver Dog was used in the search for William back in 2014 .... and that was reported on the 5th day of the search...... (Sniffer Dog PD Gov was there for 3 days)
Sniffer dogs have failed to pick up any scent of the three-year-old William Tyrell on the NSW mid-north coast, fuelling fears he may not have wandered away from home.
The search for the three-year-old who vanished from his grandmother’s Kendall home on Friday is in its fifth day – and the chances of finding him alive nearby are thought to be rapidly diminishing.
Neither police sniffer dogs nor cadaver dogs had been able to pick up any sign of the boy, Fehon said.
William Tyrell search: police say sniffer dogs have found no trace of boy | Australia news | The Guardian
The article does not specify if Cadaver Dog searched 48 Benaroon specifically, or just in the surrounding bush???
And one would have to question the accuracy of a single report??? IMO
Where as, there are multiple references of Cadaver Dogs being used in the 2021 Search for William, and at both the properties of BS and FA ......when Police carried out those searches ...
imo