“Spain (including Balearic and Canary Isles) You can continue to use your licence until 1July 2021. From 1 July 2021 you may need to take a test to exchange your licence. If you hold a licence from Gibraltar, Jersey, Guernsey or the Isle of Man, you should exchange your licence before 1 January 2021; otherwise you may need to take a test.” .gov.uk
BUT within the application period, only permits which have been verified by the United Kingdom authorities before 1 January 2021 will be redeemed, replaced or renewed.
AND it’s usually 3 days from all documents being sent off before the DGT offer you an appointment or you have to make one.
That’s why most gestorias cut off mid-December because of this. Be wary of those offering services to resolve this and taking your money up front.