Australian Car Number

[Mark McKibbin]

I was at the Austin 7 Club (Vic) 70th anniversary do and there was another 1927 car, a roadster chassis number 411?? and here is it's plate. Which sort of fits with the sequence.  I hazard a guess that all Australian cars in 1927 or thereabouts have CHA1 prefixes we probably need to enlist someone with access to Aussie club records.
So what was the sequence?
1. Chassis Ordered from Longbridge
2. Bodies are built while they are waiting for chassis
3. Bodies and chassis are united
4. Australian agents engrave number onto car no. plate. Who issues the number?
5. Body number is stamped on transmission tunnel at Longbridge or Aus?