Morris Minor Owners Club

Does any one know which , probably British Commonwealth, country used 5 digit numeric registration numbers in the 1950s ?

I have found the original reg number 12397 behind the plates on my 1953 Traveller which came back from the USA a few years ago.

Was thought possibly to be Guernsey but have drawn a black with the equivalent of the DVLA.

Any help is welcome as am trying to research its early history before it was exported to the USA in the mid 50s.

Thanks

Bryan

Was the car definitely exported to the US from the UK in the mid 50's, and not from another commonwealth country, some of who had numeric registration systems? I am thinking primarily of the trav being supplied new to a r/h/d caribbean country, maybe as an embassy or private purchase car, and then moving to the US.
What sort of plate carried the 12397 number?

Gibraltar?

problem with Guernsey plates is that they are often recycled!