Unfortunately, due to the impact of the United Kingdom leaving the EU and is no longer an EASA Member State the UK A2 CofC is not recognised in the EU
The United Kingdom officially transitioned out of the EU on the 31st December 2020 at 23.00. On the same day, the UK also adopted and bought into law the EU drone regulations.
Although the UK has adopted the same set of regulations as the rest of the EU and EASA member states, unfortunately, due to the impact of the United Kingdom leaving the EU and is no longer an EASA Member State the UK A2 CofC is not recognised in the EU.
A certificate obtained within the EU is also not recognised within the United Kingdom. If you wish to operate Unmanned Aircraft within the UK you must hold the relevant competency obtained with the UK. (You can be a non-UK resident to do the UK A2 CofC but you will need to register for a UK Flyer ID)
You can get a UK Operator ID and a UK Flyer ID by visiting this website: https://register-drones.caa.co.uk/