Aus ATC,
If there's a particular unit you hoped to work at, approach them directly. That has been known to work in the past.
Possible nationality problems have been mentioned. There's also licensing, I don't know if the UK will recognise your ATC qualifications or not. I'm pretty certain ours aren't recognised Down Under.
If they don't then I suspect the only way you could work here would be by going through the Student ATCO programme.
HTH,
WF.