Why are there two numberplates each year

Q: In the valuations section of your website, you have the option of 'choosing a year'. Thing is, there is more than one option for every year (e.g. 2007 (56) and 2007 (07). Why is this, and what's the difference between these two 'years'?
Sean Kelly

A: Since the numberplate system was revised in 2001, there have been two changes of plate each year - one on March 1 and the other on September 1.

That means that a car registered in 2007, say, could have three different 'plates'. If it was registered between September 1, 2006 and March 1, 2007 it would carry a '56-plate' - meaning the first and second numbers on the plate would be '5' and '6'.

If it was registered from March 1 to August 31, 2007 it would be an '07-plate' or, if registered between September 1 2007 and February 31, 2008, a '57-plate'.

Before 2001, numberplates were prefixed with a single letter, but because there are a limited number of letters in the alphabet, a new system was needed.

The current system is set to be in operation until 2049, so you needn't worry about further changes for a while.