In article , (Adrian) wrote:

They were, but they were number series that never got issued before
the annual suffix was introduced - so they've been kept (with others)
for issue to newly imported pre-63 vehicles or to pre-63 vehicles
that have somehow lost their original numbers.

http://fleetdata.co.uk/agerelated.html

Fascinating!

Peter Beale ) gurgled happily, sounding much like
they were saying :

Don't mind the gurgling, but why have I been pluralised? :-)

--
Peter Beale