Both before and after publication, it is a big help to be on the circuit, becoming and staying known. Younger Australian writers, at least, increasingly understand the need to travel and promote themselves. And distance isn't the only problem. An editor buying the rights to publish in London will generally also be buying the rights to Australia and New Zealand. Up new voices, Georgia Blain, Nick Earls, Luke Davies, Alex Miller and James Bradley have recently found their way onto British publishers lists.
Publishers are sheep.
Perhaps the Poms holidaying in Australia don't come in search of the Great Australian Novel, but they just might find it anyway. Carl Bridge, head of the Menzies Institute in London, markets Australia from his office near where T.S. Eliot used to work as an editor. They read something in Australia and are looking to read more of the same when they get home. I think some of the publishers are probably just starting to pick up on that, for a younger generation of readers. Australian Ben Ball is a fiction editor at Granta Books.