In France if your number plate has UK and a British flag yo do not need a UK sticker.
In Spain you do.
Do I need to put a UK sticker on my vehicle?
From 28 September 2021, you must identify that your vehicle is from the UK when driving abroad.
If your number plate includes the UK identifier with the Union flag (also known as the Union Jack), you do not need a UK sticker to drive in France.
However, you will need to display a UK sticker clearly on the rear of your vehicle if your number plate has any of the following:
- a GB identifier with the Union flag (also known as the Union Jack)
- a Euro symbol
- a national flag of England, Scotland or Wales
- numbers and letters only - no flag or identifier
If you are driving in Spain, you must display a UK sticker no matter what is on your number plate.
If you have a GB sticker, you must cover or remove it.
www.brittany-ferries.co.uk