Read the report andrew! The pilot was not given a clearance to descend to 1000', he was advised that if he wanted to transit the CTZ VFR he would have to descend to 1000'
In response to the pilot’s request, the Class D controller advised that ‘…the only way you could transit this airspace VFR would be around… not above one thousand [feet]’. The pilot responded
that the flight would descend to ‘not above 1,000 ft’ and commenced a descent from 6,500 ft. The controller had also requested that the pilot report at the 7 NM airspace boundary to receive a
clearance, but had not provided any tracking information
I'm not sure where you get this from:
2 way communication constitutes a clearance
. A clearance to descend would have been prefixed by "You are cleared to...." He was OCTA he didn't need a clearance but if he wanted to transit the Coffs control zone he would only get one at not above 1000'.
The lack of a BFR was an indication of the pilots attitude to his responsibilities as was the lack of planning and obtaining a weather forecast. When will the GA population of Australia stop thinking that if only ATC were better then VFR into IFR accidents wouldn't happen?