If all they need is to establish the AGE of the vehicle, then the chassis number stamped on the front left frame rail can be traced to 1942-45 and your local MV club should be able to give you a letter confirming that.
Dave Robinson has the chassis serial number listing up on the web;
http://homepage.powerup.com.au/%7Edjr/T214.jpg
... and he's in your part of the world too so he should be able to provide independent confirmation that chassis no xxxxxxxx is 1942-45.
If they want to know the date the thing hit Australian soil and all the previous owners and registrations, that might be more difficult.
Gordon