Dick,
Your comment, Airservices claim they cannot use "green between".
I am no longer in Australia, but used to work on the sectors surrounding WLM, and the RAAF use the same separation standards as ASA. The "green between" is used by both, BUT only when the aircraft are opposite direction and have physically passed opposite each other, ie one above the other, this correlates to the procedural "mutually sighted visual pass of traffic". If the aircraft don't do this, then either 3 or 5 nm is required.
The 3 vs 5 miles is the enroute vs approach radar sep standard.
WMF