JT,
A reply in part, re. the Chipmunk:
The deficiencies were legal process, not the aeroplane.
When the ARB certified the aircraft in UK, there was a laundry list of meaningless modifications, in my view not one of them made any difference to the safe operation of the aircraft. They cost a lot of money to carry out. Fundamentally, military and civil didn't recognise each other, much the same for pilots, SAL4 Pilot Licensing didn't recognise military qualification beyond just hours logged.
As you will well recall, the ANR/ANOs had a well defined process for certifying any aircraft to "Australian standards", which added sometimes tens of thousands of pounds/dollars to the cost of putting an aircraft on the register, and doing a "first of type" certification was a long and painful business ---- and you may recall that the number of aircraft damaged by DCA "test flying" resulted in no insurance coverage for such flying, the "Pool" said no.
Somehow or other, that process was never visited on the Chipmunk. We speculated that the most likely reason was that Sir Donald Anderson was patron of Royal Newcastle Aero Club, but we don't really know. There was no "first of type", the aircraft were just given individual C.of As.
To this day, a little seaplane, a Riviera, rests at the bottom of Pittwater, the damage to DCA's own Merlin at Mangalore, and Max Hazelton fought a long court battle to recover damages from the Commonwealth, subsequent to a test flying "event" during "certification" ---- I think that was the first Beech 1900, two cooked engines and structural damage, but not as bad as the Merlin.
Re: Southdown Engineering, think Seabird Seeker, Jabiru and several others, first degree from Sydney (we started Engineering the same day) and long time in DCA in Melbourne in Airworthiness early in his career. Later, engineering-wise, ran the CSIRO F-27, for all the interesting things it got up to. Headed up the Airworthiness Tec. Subcommittee of the CASA Review from 1997-1999. First person to hold a CASA delegation to sign off for a Type Certificate, other than a CASA employee ---- an idea stoutly resisted by the "iron ring" in CASA, but an intent of Part 21.
Tootle pip!!