Just a quick update for those concerned.
The Oberon ambulance service located the downed rider and got him back to Oberon. He has since been transported to Sydney.
##Important lesson##
Never ride in remote areas in a party of less than 4 riders!!!
(1 stays, 2 go for assistance)
Crash
PS. It will come out in the Caves ride reports, but we came across 2 blokes on the track on our return today. One had a BMW1200 land on his leg after losing traction on a slippery uphill section of the track. It spun around and crunched his leg under it. We made him comfortable, reassured them, gave them a silver warmth blanket, changed our route home and arranged some help for him.