I think I can help you answer this question. I learned to cook in a restaurant kitchen as a teenager. I worked in advertising for 15 years, mainly working on food brands and studying how British families shop, cook and eat. I then set up my own food retail company to feed hungry commuters in London. My favorite food.
Lunch: Sandwiches are by far the most popular lunch. Usually more basic, cheese, ham and salad, tuna mayonnaise and chicken salad are favorites. Usually eaten with a bag of potato chips. Savory is the most popular flavor. This may be followed by a piece of fruit and/or a chocolate chip cookie. Salads are also popular in the summer, and soups are popular in the winter.
Lunch: Sandwiches are by far the most popular lunch. Usually more basic, cheese, ham and salad, tuna mayonnaise and chicken salad are favorites. Usually eaten with a bag of potato chips. Savory is the most popular flavor. This may be followed by a piece of fruit and/or a chocolate chip cookie. Salads are also popular in the summer, and soups are popular in the winter.
Dinner: What different British people eat is so different that it is impossible to eat them all. But generally speaking, many households in the UK usually cook ten dishes, and occasionally cook something different. Typical examples include some or all of the following
Roast dinners are very popular. Maybe not every Sunday, but the average family probably does it regularly. Other popular traditional British foods such as shepherd's pie, fish pie, sausages, mash, casseroles, mince pies and lamb chops are also popular.
Spaghetti Bolognese/Lasagna/Tuna Lasagne (unlike the Italian original, the attitude here is to experiment and add whatever you like rather than sticking to a proven recipe) You might Not even using spaghetti but still calling it spaghetti bolognese. Usually served with garlic bread or salad. Scotland is the country with the highest per capita consumption of pasta after Italy. Pizza is also very popular, especially among children and young adults.
Curry is also very popular. Most likely Indian, but Thai and Malay styles are also popular. The most ordered dish in British restaurants is chicken curry.
Chinese food is also popular, especially stir-fry dishes with noodles or rice.
Takeaway is also popular, especially on Friday and Saturday nights. Sorted by popularity; Chinese, Indian, fish and chips, pizza. Chinese takeaway bears no resemblance to real Chinese food, it was adapted to cater to British tastes 50 years ago and hasn't really changed. (My ex is Chinese, so I've had authentic Chinese food both at home and in China)
British people eat a lot of different things, and British culture is very good at absorbing foods from other cultures. With connections to history around the world, the average family will eat food from different cultures around the world.
The town I live in has about 65,000 people and has restaurants serving British, Chinese, Japanese, Thai, Malaysian, Italian, Pizza, Turkish, French, "Modern European", Spanish, Greek, Mexican, American Smokehouse, gourmet burgers, Italian, Middle Eastern and Lebanese food and a French/Indian fusion restaurant. There were also street stalls selling Peruvian food, paella, Jamaican food and a few others I can’t remember. Go to London, half an hour away, and you can buy food from all over the world.