However for expats with a UK licence they recommend this:-
Driving licence exchange for UK nationals living in the EU
If you are a UK licence holder living in the EU or EEA you should exchange your UK driving licence for a local EU driving licence before 29 March 2019. From that date, in the event that there is no EU Exit deal, you may have to pass a driving test in the EU country you live in to be able to carry on driving there.
You should consider exchanging your UK driving licence for an EU driving licence as soon as possible. Increased demand may lead to longer processing times and delays to exchanging driving licences the closer it is to 29 March 2019.
From our point of view (living in the UK and in possession of a UK licence), we need to carry two IDPs, a 1949 for Spain (and perhaps Turkey as they keep changing their minds) and a 1968 for all other EU countries and perhaps Turkey if they won't accept a 1949.
We've already purchased a one Year 1949 but will be travelling to our nearest post office tomorrow (again in Swansea although they have added 2500 extra outlets to the UK list ) to get a three year 1968.
Randa