I can probably answer some of those questions. In numbers with an X, this is a place holder which was not used until ADR's were introduced. The letter D denotes a list of ADRs which would have applied to this vehicle. We left it as X since there could be several letters which could go here. THe unformatted list below shows what the letters mean, but for the online tool, it will only accept the X.

Our web site will show what was supposed to happen with vehicle identification, not what actually happened. In many cases, vehicles were wrongly stamped. As a fixed point of reference, we stay with the official intention rather than what was actually stamped.

There are no plans to update the web site at this stage.

Symbol Interpretation Rule Numbers Models
X Spare position Indicates ADR compliance for vehicles before Jan 1973.
A After January 1973 1, 2, 3, 4, 5A, 6, 7, 8, 9, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26 Automatic Vehicles
B After January 1973 1, 2, 3, 4, 5A, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26 Manual Vehicles
C After January 1973 1, 3, 4, 5, 6, 7, 8, 10B, 11, 12, 14, 15,16, 18, 20, 21, 22, 24, 25, 26 Moke
D After January 1974 1, 2, 3, 4A, 5A, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22, 23, 24, 25, 27, 28 Manual Vehicles
E After January 1974 1, 2, 3, 4A, 5A, 6, 7, 8, 9, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22, 23, 24, 25, 27, 28 Automatic Vehicles
F After January 1974 1, 3, 4A, 5A, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22, 23, 24, 25, 27, 28 Moke
G After January 1974
1, 2, 3, 4A, 5A, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22, 23, 24, 25, 27, 28 Mini Van

After January 1975 1, 2, 3, 4B, 5B, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22A, 23, 24, 25, 27, 28 Mini Saloon
After January 1975 1, 2, 3, 4B, 5B, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22A, 23, 24, 25, 27, 28 Mini Van
After January 1975 1, 3, 4B, 5B, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22A, 23, 24, 25, 27, 28 Moke
After January 1976 1, 2, 3, 4C, 5B, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22A, 23, 24, 25, 27A, 28, 34 Mini Saloon
After January 1976 1, 2, 3, 4C, 5B, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22A, 23, 24, 25, 27A, 28 Mini Van
After January 1976 1, 3, 4C, 5B, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22A, 23, 24, 25, 27A, 28 Moke
Note: ADR27A introduced 07/1976 all models.
After January 1977 1, 2, 3A, 4C, 5B, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22A, 23, 24, 25, 27A, 28, 29, 31, 34 Mini Saloon
After January 1977 1, 2, 3, 4C, 5B, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22A, 23, 24, 25, 27A, 28, 29, 31 Mini Van
After January 1977 1, 3, 4C, 5B, 6, 7, 8, 10B, 11, 12, 14, 15, 16, 18, 20, 21, 22A, 23, 24, 25, 27A, 28, 31 Moke

The decoder lists all BMC/Leyland models produced in Australia including identification for those vehicles which was assigned, but the vehicle not produced (e.g. Force 7). The decoder does work for nearly all of the 400 odd models produced at the factory during its lifetime, but like I said, there are always some cases in which the codes were wrongly assigned and wrongly stamped. All the Austin 1800 MKI's, for example, are stamped with the code for the Austin Lancer Series II. This was not a mistake by the guy doing the plates. An error was made in the Engineering Dept and it got carried through before anyone realised it. You have to draw the line somewhere with these sort of things, and we drew it at what was the official standard. Where we know of something wrong, we've put a note in our reference book. The online tool is just something simple, it isn't intended to provide a resource for every undocumented variation.

Figure below shows what I believe to be YKG2S4 bonnet badge. Never seen one in person, but goes to show how far things went with the development of this model.

This discussion is probably straying a bit from the original thread topic,

I have asked Peter, whose job it was to actually delete the marque code and assigned body numbers, to try and get a more precise date at which the marque code was dropped. No one i've spoken to so far has actually seen a car stamped YKG2S4, but it is possible that some early cars may have been stamped that way.

I have seen early Ks with ID plates stamped YMG2S1. I have always assumed the early Mk2 Cooper S may have still had the missing digit.