There are also rules on the importation of food into the UK- at the moment it is not allowed to import any dairy or meat (poultry and fowl is still OK) from the EU into the UK.

https://www.gov.uk/bringing-food-int...nimal-products

Fish is currently allowed. But his list does change rapidly at the moment according to health risk.

Therefore I'd simply courier any tinned fish straight from France to Amsterdam and save the hassle.