For two adults, I spend about £35/week, shopping at two supermarkets (Aldi and Morrisons). This includes a bottle of wine and fancy cheeses, but no crisps, biscuits, ready meals.
In addition, I spend (on average) about £10 / week at my local butcher's.
All meals are taken at home. We eat very well (I think).
Lunch is usually a salad, or soup with something else. I am ruthless about portion size with regard to meat though: 100g/person only, so one chicken fillet will typically feed us both.
For dinner, we probably eat fish twice a week (one dinner with fresh fish, one with tinned tuna) and have meat 3/4 times, so once or twice a week, we will have a vegetarian option.
To really save money on your supermarket shopping, you have to switch to Aldi or Lidl and you will probably pay only 2/3 what you pay for similar goods at Tesco/Sainsbury's. However, a lot of people find that they cannot get all the stuff they want at Aldi/Lidl so you might still need to do a top-up shop at another supermarket.
If time is of the essence, you may want to try either Aldi/Lidl and do a big shop there ever fortnight or so, and buy the complement at your usual supermarket.