So, how about Dick Johnson? Yes, he's a bit older. But he has quintessential Australian humour, knows his cars, is opinionated, not very PC and can even drive a bit. Those old enough to remember his in-car running commentary during 1980s Bathurst races will know what I'm talking about. And if Dick isn't available, then John Bowe might make a good choice (and please how about a track test of his Gallardo GT3 racecar?).
Dick Johnson would be great but as you said age would be a probelm as he must be around 70 years old now.