Hi Steve.
Not wanting to get into an argument, but the compliance plate only tells part of the story.
With anything BMC or Leyland, confusion is par for the course.
As I pointed out in my first post, the company name up until March 1973 was British Leyland Motor Corporation (Australia). This name is on the compliance plate on the blue 1971 Clubman.
This information is from much previous research, although I cannot locate the reference just at this time. However, in the new book by the Leyland Australia Heritage Group, titled Building Cars in Australia, it says the company name changed in December 1971. I will look into this a bit further. It may be, and I could stand corrected, but I am reasonably confident, that there was a subtle name change in December 1971 to The Leyland Motor Corporation of Australia, followed by a further name change in March 1973 to simply Leyland Australia (however, see the 1981 compliance plate below).
The compliance plates on the two Mini S (Gambier Turquoise and Plum Loco cars above) both illustrate this - to make the change easily and cheaply (a Leyland trait, no doubt) the word "British" was simply ground off the tooling for the plates.
This change on the compliance plates appears to have taken place around May 1972.
Compliance plate from March 1972 Clubman GT - note the British is still on the plate.
Compliance plate from May 1972 Moke. Note: Mokes at this time were sold as BMC Moke - the only cars sold in Australia as BMC branded (I think). In fact, the Moke had a BMC Moke badge on the front only in 1968 to 1969 or 1970, then the front badge only said Moke, but they were still sold and listed as BMC Mokes. In 1973 they became Leyland Mokes, even though the front badge still only said Moke.
Compliance plate from 1981 Moke - note that this is a new pressing, rather than just having the word British ground off the dye, but still says Leyland Motor Corporation of Australia.
Getting back to 1971, the homologation papers for the Clubman GT clearly state the car is a Morris.
As in the UK, when British Leyland was established in 1968 (1969 in Australia) the car division was renamed the Austin-Morris division. In 1971 (in the UK) the Mini was designated under its own brand name and Morris and Austin versions were deleted - however, other car models remained as Austin, Morris, etc: such as the Austin Metro. Other name changes followed.
In Australia, the cars remained as Morris or Austin up until 1973, when the company name changed and all cars were relisted as Leyland cars. These included the Morris Marina, which in 1973 became the Leyland Marina, and the Austin Kimberley/Tasman (discontinued in 1972).
The Mini was still sold as a Morris up until March 1973. The name on the compliance plate refers to the manufacturing company, not the brand of the car.
Compliance plate from 1971 Cooper S. Note that the car is described as Morris YG2S4, even though the manufacturer is The British Leyland Motor Corp of Australia.
With the introduction of the square-front Minis in mid-1971: YG2S6 Mini 1100; YG2S7 Mini Clubman and YG2S8 Mini Clubman GT, the compliance plate changed from Morris to Mini, but the cars were still sold as Morris.
Confusion reigns because by this time the Mini was being promoted in advertising as simply Mini in its own right, and the situation is often made worse because of press reviews of the cars. Wheels magazine, for example, wrote: "British Leyland pops its new Mini Clubman range onto the market...". This is accurate, because the cars were built by British Leyland, but misleading because they were not sold as Leylands.
Back page from the March 1971 brochure for the Mini Clubman and Mini Clubman GT (the cars were released in August 1971, but obviously the brochures, handbooks, etc had to be printed prior to the launch). Note, right down at the very bottom of the page, that the brochure was produced by the British Leyland Motor Corporation of Australia Limited - Austin Morris Division.
So, as I said, for the first month or so of production, the Mini Clubman S was built by British Leyland Motor Corporation of Australia, even though the compliance plates had already changed to Leyland Motor Corporation of Australia, and from March or April were built by Leyland Australia.
Yes, it is all quite confusing, but this is how I understand it after many years of research on the subject.
Cheers,
Watto.