...To Steve,
For "dumping" oil all over your (incidentally, VERY nice Celica), in the "run" home to Canberra...
I'll re-iterate that, we had the seal checked (and replaced) when the diff went in, and the half-shaft on the LHS replaced on Thursday when we found it leaking, and also checked it on arrival in Dubbo - no leaks - so we "weren't to know".
Still, it doesn't change the fact that your car got sprayed with oil...so, apologies!!!
At least it didn't "let go" at *insert appropriate speed here*!