We have 6 self catering weeks every year, in different places round the UK. We've done this for 9 or 10 years now.
We take vacuum packed bacon, Black Farmers sausages for me and Lincoln for Mr. Blue, eggs, tomatoes, cherry toms, mushrooms, fresh steaks for one meal, condiments, butter, cheese, yogurt, various things for Mr. Blue, wine boxes, tins of salmon for my picnics, mayonnaise, pickled onions, plenty of Lidl HP rolls (essential), tea, coffee, and lots else.
If travelling a long way we stop off en route for frozen veg and berries, otherwise we take them in a cool bag. We always use Google for supermarkets, butchers and so forth near the cottage so we can replenish our stocks.
breakfast for me is just my coffee and cream. Mr. Blue has other things.
Picnics every lunch time with maybe one or two lunches in a dog friendly pub or cafe.
Meal in the cottage in the evening, but always easy to cook quick ones. No slaving over a hot stove.