For those who are interested I've ordered a o2 sensor from Repco (the $29 clearance ones). They still have a couple out there. Mine's coming in from Broken Hill but apparently there are 2 in Whyalla and 1 somewhere in Darwin. That was coming from the mumblings of the Rep at Blair Athol. But regardless he was very helpful and ordered it in for me. So all up it's $29 plus freight.