Hey Cupcake, where are you in the UK? I'm down in Bristol.
Some suggestions, do you like beans on toast? It's very British and has become a comfort food for me. Cheap and healthy if you use low salt/sugar Heinz BB and whole meal bread.
Buy a package of 2 chicken breasts, grill both at the same time and have one for that meal and one in the fridge for the next day (can be used as chicken salad or sandwich) You can also buy curry paste's for the chicken or a tikka rub which could be stored easily since they are usually small jars.
For breakfast you could have rolled oats, easy to cook and no leftovers. Buy some dried fruit or banana to toss in it.
Eggs, like Aunt Dot suggested. Loads of things you can do with eggs.
College Cook has some great suggestions for group meals, but thats only if everyone in the house is up for that.
For the pantry, whole wheat pasta. You can just use the amount you need for one meal. Couple tins of tomatoes for sauce and some dried herbs. Ground beef you could freeze in single servings so only having to defrost and use enough for one meal.
Not sure how you feel about brown rice but its cheap and very healthy. You can buy a bag and just cook enough for one serving. Maybe with your chicken, you could do rice with veggies. You can also buy bullion cubes (chicken, beef or veggie) to cook the rice in and they are cheap and small to store. You could also do some sort of fried rice dish with any veggies you have, carrots, peppers, onions and maybe the chicken breast too!
Buy sweet potatoes instead of white potatoes and mash them up or roast them. Olive oil is something you should have on hand. I would love to suggest some soups but you would have leftovers!
And for fun check out this link BEYOND BAKED BEANS - Cheap healthy food for students and singles
The site is aimed at cheap and healthy foods for students, singles or anyone on a budget. Have a looksee!
Hope some of those suggestions help! :)