I still find it bizarre how quickly the knives come out in Australia. There are two reasonably similar times this happened in Canada (Dief '67, and Clark '83), and in both cases the enemies of the leader didn't try anything until they had actually lost an election 
Or, in Dief's case, two consecutively
But, in Canada as I understand it, it's much harder to force a spill motion -- for instance, I've read that a majority of Liberal Party members preferred Paul Martin over Jean Chretien starting from the late '90s, but Chretien still hung on until 2003.
