My neighbour has a house in France, voted Brexit as there are 'too many polish people in this country' and is now frothing because she will need 4 months notice with the vet, in order to take her dog with her, to France.
I think the 4 months notice relates to the first trip abroad;
"Before your dog, cat or ferret can travel to the EU for the first time after 1 January 2021, you’ll need to take the following steps..."
"As long as you keep your pet’s rabies vaccinations up to date, you will not need to get repeat blood tests for repeat trips to the EU."
www.gov.uk/guidance/pet-travel-to-europe-from-1-january-2021