Thanks for the info Leadsled.
Unfortunately I cannot find anything in the CASR's or MOS about establishment and disestablishment criteria relating specifically to the determination of whether an Airport will be ATC controlled or not.
It refers to ARFF which is straight forward - the category determined by ICAO guidelines in the ICAO Airport Services manual and Cat 6 and above in Australia supplied with the service through ASA. I thought a similar clear cut process would be in place for a deciding if a tower service was required and was my original motivation for the post as I couldn't find a reference similar to the ARFF criteria. It appears the process may be a little more subjective (and contentious) given some of the examples listed in this and other similar threads on the issue.
I have reworded my work and referenced the Airspace Regulation 2007. It was the closest thing I could find given the context of the paper.
Thanks again for the replies. It is appreciated.