I'm not familar with UK food prices, but how much are these staples? You can build tons of meals and snacks on these:
Coconut milk: 400ml tin costs £0.99
Almond butter: 170g jar costs £2.39
Spinach: 260g pack costs £1.00, has a warning that it goes off after 2 days
Kale: 206g pack costs £1.00, has a warning that it goes off after 5 days
Frozen raspberries: 300g pack costs £1.39
Frozen strawberries: 500g pack costs £2.00
Frozen blueberries: 350g pack costs £2.00
Salmon: 200g pack of fresh smoked salmon slices costs £2.79, or 300g pack of frozen smoked salmon costs £3.50
Tilapia: 110g fillet costs £2.00, has a warning that it goes off after 2 days
Ground beef: 500g pack costs £3.50, has a warning that it goes off after 4 days
Scallops: 160g pack of raw scallops costs £3.00, has a warning that it goes off after 3 days, or 200g pack of frozen scallops costs £6.50
Shrimp: 200g tin costs £1.08
Chicken thighs: 900-1110g pack costs £3.89, or 566g pack of mixed thighs/drumsticks costs £1.49
Canned tuna: 185g tin costs £0.66
Canned salmon: 212g tin of pink salmon costs £1.09
Butter: 250g pack costs £1.19
Eggs: box of 10 costs £1.19
Bacon: 220g pack costs £1.59
Bell peppers: mixed pack of 3 costs £1.65, or red, orange, green or yellow peppers cost £0.78 each
Carrots: 640g pack of sliced carrots costs £0.96, has a warning that it goes off after 3 days, or 1.2kg pack of raw carrots costs £0.55
Ham: 400g pack of sliced ham costs £1.65, has a warning that it goes off after 8 days
Mushrooms: 250g pack of sliced mushrooms costs £1.00, has a warning that it goes off after 2 days, or 380g pack of closed cup mushrooms costs £1.00, has a warning that it goes off after 2 days, or 300g pack of large flat mushrooms costs £1.20, has a warning that it goes off after 3 days
Cheese: 250g pack of sliced cheddar costs £1.80, or 350g block of cheddar costs £1.99
Greek yogurt: 500g tub costs £1.00
Cottage cheese: 300g tub costs £0.60
Rice: 1kg pack of long grain rice costs £0.40
Potatoes: 850g pack of ready peeled potatoes costs £1.00, has a warning that it goes off after 3 days, or 2.5kg pack of raw potatoes costs £0.67, has a warning that it goes off after 3 days