I guess I am lucky in that I've had a few trips to Aus now and have spent all of the time there living/staying in houses long enough to get an idea of what the differences are.
Another big one for me is the adjustment of the layout of the houses. The British are used to two floors as a rule, living down, bedrooms up. However many Aussie homes tend to be single floor and are longer than wider from the street view. And often will have bedrooms at the front of a house and the living ones (kitchen/sitting/dining) at the rear or sides. Also pretty much every Aussie house has a utility room of some shape or form. And showers are the rule, not baths.
I often notice on those moving down under shows that families comment and don't like the bedrooms at the front (esp those with kids) and its always seen as a down side to a property. What they don't seem to realise is that many homes are laid out in similar ways and finding a house with sitting room at the front and all bedrooms at the back is pretty rare (at least in the houses I've seen, usually always one/two of the bedrooms at front/side somewhere).