Hi Murray:
You mentioned anti-tank "battalion" and I thought I might mention the the RAA like its Commonwealth sisters (RA, RCA, RNZA) use the term "regiment" to describe a battalion sized organisation.
For lots of great info on the RAA see:
http://australianartilleryassociation.com/
http://www.defence.gov.au/ARMY/RRAA/default.htm
http://en.wikipedia.org/wiki/Royal_Australian_Artillery
You'll find that the Gunners are a warm and welcoming bunch and will be keen to help you out with research into your vehicle's history.
Welcome to the C8/F8 club!
Mike