From the British Embassy- The special measures put in place by the Spanish Department of Transport for UK nationals to exchange their driving licence have now been extended, so that the deadline to register your request to exchange is now 31 January, although we would advise doing it as soon as you can.
Some other points of clarification that might be useful:
It doesn’t matter if your UK licence is expired or lost. If the licence has expired, you should follow the instructions for ‘renovación’. If lost, follow the instructions for ‘sustitución’.
You can start the process (online or by calling 060) with a NIE, even if you don´t have your green residency document. The first step of the process is essentially asking the Spanish authorities to verify your UK licence. The formal request for exchange is done once you go in for your appointment at the DGT. At that point you will need a valid residency certificate.
If you started the process in October you can now request an appointment at your Jefatura Provincial de Tráfico.
If you started the process in November, or are about to start the process, you can request an appointment at the JPT two days after registering your details. The DGT recommends that you continue using the special measures for UK licence holders.
You can continue to send us direct messages with any specific issues and we will feed your questions back to the DGT.