Paul McLean (56)
I loved Scott Higginbotham.You're forgetting Scott Higginbotham, what an outstanding player, Wallabies won the 2011 Tri Nations with him at No.8, he was a big factor to their success 2010-2011 (Elsom, Pocock, Higginbotham) - a world class backrow coached by the outstanding David Nuicifora who was breakdown/forwards coach at the time, who's now leading Ireland to unprecedented success - everything comes back to Nuicifora.
But - he did get multiple chances and under more than 1 test coach. Ultimately I don’t think you can say he was consistently successful at test level. Guys like McMahon, McCalman and others all had some level of sucess at test level. None achieved sustained success.