I see that the UK Supreme Court handed down an interesting decision recently in Flood v Times Newspapers Ltd [2012] UKSC 11 (21 March 2012)
http://www.bailii.org/uk/cases/UKSC/2012/11.html on the scope of the Reynolds "public interest defence" in the law of defamation. The newspaper was justified in publishing allegations about, and the name of, a police officer in a senior position accused of corruption. Reynolds, of course, is not part of the law of Australia, but there are some interesting dicta on public interest generally which may be persuasive for Australian courts in applying, say, the Lange defence of qualified privilege or statutory version of QP.