Yes, the Newbery's sell in AUS too, but again I am not sure if they are as popular as the Kookaburra's or the GM's
Many bats made in India and Pakistan probably sell in more countries than Newbery but that does not make them big brands with exceptions.
Going by my experience, I would say Newbery's are more popular with slightly older players (thought the UZI has really picked-up among the younger players) and players with a more classical / technically correct playing style.
In fact, I plan to travel to Hove and get either a Newbery UZI or get my Puma Millichamp replicated.