Sorry to be the bearer of bad news, Steve, but that is not actually correct.
The Clubman GT, and in line with that the Clubman, was in fact listed as a Morris. The CAMS homologation papers for both the regular Clubman GT and the police-spec Clubman GT list the cars as Morris. The brochure for the 1973 line of Minis, the Leyland Mini and Leyland Mini S, says "1973 sees the first Leyland Minis on the road"
The Mini Clubman S appeared right at the time of the change-over from British Leyland Motor Corp (Australia) to Leyland Australia, in March 1973, and with it a change to badging the cars with Leyland Australia badges on the front A-pillars and in the steering wheels centres, instead of the previous British Leyland badges.
1971 British Leyland badge
1973 Leyland Australia Badge
Within a few weeks the name change took place and the car became known as the Leyland Mini S, with both the Mini 1100 and Mini Clubman being replaced by the Leyland Mini.
This compliance plate is from a March 1973 Mini Clubman S. Note that the S is not listed.
However, it is listed on the next plate, for a May 1973 car, while the car number prefix is still 022 A2S2 - because both the Mini Clubman S and the Leyland Mini S were variations of the YDO22 Mini Clubman. Although not listed as a Leyland, by this time it certainly was, and the Mini Clubman had been deleted in April 1973.
The next compliance plate is from a 1971 Mini Clubman. Note that the car prefix is YG2S7. This number prefix system was replaced with the 022 system in January 1973, so all Mini S, whether Clubman or Leyland, should be listed as 022.
This compliance plate is from a 1974 Leyland Mini and you will see the prefix is 021, as these base-model Minis were considered a variant of the YDO21 Mini 1100.
So, getting back to the original question, the Mini S was only introduced in March 1973 and was technically a Morris Mini Clubman S, but by the following month was a Leyland Mini S.
While the change-over from Morris to Leyland took place in March 1973, it appears that the first few cars (the pictured compliance plate is from car number 550) would have been badged according to plans made before the change and that by the time the cars had actually been built the change had come into effect.
It is not known how many cars would have been built as Mini Clubman S, but as the production rate at the time, for all saloon model Minis, was only around 500 per month - note from the above compliance plates that there were around 600 Mini S built by May 1973 - it would be fair to suggest the number would have been no more than around 200 or so.
For more information, see Issues 12, 19 and 20 of The Mini Experience.
Cheers,
Watto.
