This is a bit of a can of worms...
I don't think there's much difference between an Aussie degree and a U.K. degree; my 3 year Bachelors degree in Mechanical Engineering from the University of London was accredited as being the equivalent of a 4 years US Bachelors degree.
The problem though, is that most companies use some sort of computerized sorting of initial apps. You could tick the "I've got a 4 year degree" box, which you do, sort of and then have to explain it an interview or you don't tick that box and never get called.