Generally, UK photo card license holders will not need an International Driving Permit (IDP) in order to drive in the EU/EEA after Brexit. However, you may be required to have an international license in addition to your UK domestic license to rent a car in certain EU/EEA countries if:
-You do not hold a photo card license (i.e. you have a paper license).
-Your license was issued in Isle of Man, Jersey, Guernsey, or Gibraltar.
You can easily obtain an IDP at your local UK post office. You can read more about driving in the EU after Brexit on the Post Office website - https://www.postoffice.co.uk/identity/international-driving-permit, or the GOV.UK website - https://www.gov.uk/driving-abroad/international-driving-permit.