Re: good grief
Which is an absolutely terrible way to run things. Why use letters at all? As far as I know, anyone else outside UK only uses letters as a prefix to identify a region. (again, not really sure why but I presume in the era before digitisation each local office could keep its own house in order)
Surely it's far more sensible to have only letters or only numbers, and if you want to identify registration year or half year put it in front or tag it on at the end instead of randomly plonking it down in the middle.
I know, far too sensible for a committee of buerocrats