> In Australia, coffee would normally be consumed as a dark roast

I live in Sydney and I mostly drink espresso shots (no milk), the roast is very noticeable to me due to the type of coffee I drink.

I would say at least half of all cafes that I've tried use a light roast for black coffee, and dark roast for milk-based drinks.

Italian-style cafes and non-specialty big chains, use dark roast for everything. But that's becoming less and less common especially in fancier establishment.

This is based on my experience in the CBD, Lower North Shore and Inner West. YMMV