I noticed in the Telegraph motoring section "Car advice with Honest John" Q & A 's

In the recent past it has been the case that expats adopt overseas driving licences. Is this still the case? NR

Yes. You can't have a UK licence without a UK address for the very obvious reason that you couldn't be checked or penalised.

Not correct HJ - The DVLA is happy for expats to retain their valid driving licence when living abroad, but it cannot be renewed when it expires if the holder is not resident in the UK, whether or not they have a UK address.

Whether or not it is necessary to exchange the UK licence for the licence of the country where the expat is living depends on the law of that country.

In France for example, it is not necessary to exchange the UK licence for a french one unless one commits a driving offence, so that they can award points, which they can't do on a UK licence.