Here's a summation which, as I work with British visitors to France, might also be useful for SD Members?
It does tend to "repeat" but it is all cut and pasted from the various rules that can be found here and there on You Gov website so is helpful regarding fish and other items plus the difference between bread and bread made into sandwiches.
I hope it helps? So at least one can still bring back a "poulet de Bresse" and similar.
Bringing food into Great Britain
Government extends ban on personal meat imports to protect farmers from foot and mouth
Ban on personal imports of meat and dairy products extended to cover all EU countries to safeguard the UK food system and farmers against foot and mouth disease.
The Government has taken measures to prevent the spread of foot and mouth disease (FMD) following a rising number of cases across Europe.
From Saturday 12 April it will be illegal for travellers from all EU countries entering Great Britain to bring items like sandwiches, cheese, cured meats, raw meats or milk into the country. This is regardless of whether it is packed or packaged or whether it has been bought at duty free.
Travellers will no longer be able to bring cattle, sheep, goat, and pig meat, as well as dairy products, from EU countries into Great Britain for personal use, to protect the health of British livestock, the security of farmers, and the UK’s food security.
You can bring the following into Great Britain from any country without any restrictions
bread, but not sandwiches filled with meat or dairy products
cakes without fresh cream
biscuits
chocolate and confectionery, but not those made with a lot of unprocessed dairy ingredients
pasta and noodles, but not if mixed or filled with meat or meat products
packaged soup, stocks and flavourings
processed and packaged plant products, such as packaged salads and frozen plant material
food supplements containing small amounts of an animal product, such as fish oil capsules
The rules on bringing meat, dairy, fish and other animal products depend on the country you’re bringing it from.
From the EU, Switzerland, Norway, Iceland, Liechtenstein, the Faroe Islands and Greenland
You can bring in the following for personal use:
fish
poultry, for example chicken, duck, goose and any other products made from these meats
other animal products, for example eggs and honey
Because of animal disease outbreaks (including foot and mouth disease) in the EU, there are temporary restrictions in place for bringing in:
meat, dairy and animal products from some animals
animal products not for human consumption
You cannot bring in food from other countries on a connecting flight.
You need to properly dispose of any leftover animal products so that livestock, wild boar and other animals cannot eat them.
Restrictions on meat, dairy and animal products for human consumption
You cannot bring in any of the following:
pork
beef
lamb
mutton
goat
venison
other products made from these meats, for example sausages
milk and dairy products like butter, cheese and yoghurt
You can bring in up to 2kg per person of powdered infant milk, infant food, or special food needed for medical reasons. You can only bring it in if it does not need to be refrigerated before use, and is in branded, unopened packaging (unless in current use).
From countries outside the EU
If you’re bringing food from a country outside the EU, Switzerland, Norway, Iceland, Liechtenstein, the Faroe Islands and Greenland, the following rules apply.
You cannot bring in:
meat or meat products
milk or milk-based products, except powdered infant milk, infant food or special food (including pet food) needed for medical reasons
You can bring in up to 2kg per person of:
honey
powdered infant milk, infant food, or special food (including pet food) needed for medical reasons - you can only bring it in if it does not need to be refrigerated before use, and is in branded, unopened packaging (unless in current use)
shellfish, such as mussels or oysters
snails - these must be preserved or shelled, cooked and prepared
frogs’ legs - these must be the back (hind) part of the frog with the skin and internal organs removed
insect meat
You can bring in up to 20kg per person in total of fish, including:
fresh fish - must be gutted
fish products
processed fish - must be dried, cooked, cured or smoked
lobsters
prawns