As an aside, the note has a theme of "science". The two personages who appear on this note are:
Front:
Howard Florey, arguably Australia's greatest scientist of the 20th century and the inventor of the technique for mass-producing penicillin, for which he won the Nobel Prize for Medicine. Also on the front are depictions of the penicillium mould growing in petri dishes, and the Sir William Dunn School of Pathology at Oxford University.
Back:
Ian Clunies Ross, founding chairman of the government scientific organization, CSIRO. Included in this complicated secondary design are the Parkes radio telescope, along with a radio map of the galaxy. As a numismatic aside, Ian's second-cousin was John Clunies Ross, owner of the Cocos-Keeling Islands and issuer of the tokens which bear his name.