It seems that you don't need an IDL ( International Driving Licence ) to drive in Portugal post Brexit ( that is, if it ever happens....) , but you will if driving down through France, but not if only through Spain, see :

https://www.gov.uk/guidance/driving-in- ... ng-permits

Some good news anyway!

I purchased mine on Thursday this week

Brought both of mine just in case! One lasts a year, the other for 3 years. Problem is can’t remember which is which, need to check online!