"Martin Underwood" wrote in message
...

Maybe the boundaries have become a bit more
blurred and the regions have got larger (like a two-letter code in a car
registration number used to relate to a specific town, whereas now it
relates to a group of counties).

Actually, to be pedantic, they still do (to a degree). The first character
is the registration district, the second is the registration office. So, for
example, in a registration such as AA54 ABC: AA indicates Anglia district,
Peterborough office (as would AB to AN). AO to AU are Anglia district,
Norwich office and AV to AY are Anglia district, Ipswich office.