Yup... was going o mention that, but you beat me to it. A few years overseas will cure anyone of that mistake ;)
When I first came to Japan, they all sounded alike... had a few acquaintances from the 3 (UK, Australia, and NZ)... first roomate was from NZ... Can now hear a pretty big difference between all 3.
Speaking of being overseas, when I lived in England, I got so I could darn near pinpoint what part of the country a Brit was from, by their accent. They were that distinct.