The licence number on a UK licence doesn't change. It is made up of the following:-
1st 5 letters of your surname, your date of birth jumbled up, your initials followed by a random number and 2 random letters.
I haven't changed mine for the same reason Biddy, lasts until the day before your 70th birthday...after that you have to reapply every 3 years, after taking a medical.
If your licence is that tired mickeymc, why not write to Swansea and ask for a replacement? You'll get a card instead.