Well this is why YMML spent a small fortune on a CAT III system.
Don't know about QF but VA appear to be using CAT II only as they have been delaying flights and had some go missed and divert with RVR < 400m or so. Captain on my flight last night gave a long description of 400m being the minimum required.
Even some INT missed out yesterday so clearly use of CATIIIb isn't universal.
I gather Australia does not have any Cat 111 or Cat 11 runways?
Melbourne is Cat III, Sydney is Cat II, the rest are CAT I