Gammon shanks are cheap to buy (£1-1.50 each) - just boil and u can shred the meat for stir-fry, pasta sauce, sandwiches, pie-filling. Morrissons do them i think... or highstreet butchers.
Big cheesy potato pie (mash, chopped onion, bit of cheese then grated cheese on top) will last for a few days and goes with everything. Wedges are cheap and easy, use spices to make them more exciting.
Cheap fish pie - use cheap fish like value smoked mackerel, then one piece of frozen 'white fish' (most supermarkets to own brand cheapo versions) and some frozen peas (or cheaper, a sliced leek), cover in homemade white sauce (melt some butter or oil and add flour to a paste, then add milk that you've heated up with an onion in bit by bit so no lumps) and then cover with mash and oven.
Mam used to make a massive saucepan of peeled spuds, quartered peeled onions, a few peeled carrots and a few slices of bacon on top (or bacon bits - Lidl do a big pack of offcuts cheaply) all boiled until done. Simple but lush.
Chicken livers are cheap (99p for a big box, enough for 4 ppl) and are lush stirred through a pasta sauce, or on sexy toast (garlic-rubbed, thick), or in risotto or a salad.
Pearl barley is much cheaper than risotto rice and works brilliantly in salads, soups, as a carbs option instead of pasta/potatoes, or cold in salads to bulk them out.
Good luck and keep us posted! :)