Easy cook recipes, UK

If you want to be full up eat protein or good fat (avocados) and lots of fibre foods like vegetables (not potatoes) and fruit.
Eggs are quick and contain protein (try a frittata, layer sliced veg in a dish and pour over beaten egg, bake until cooked through)
Fish is quick and contains protein (try making a spicy sauce with a tin of chopped tomatoes and poach the fish in it, serve with steamed veg)
Red lentils are super quick to cook, contain protein and fibre. (look up dal recipes online, you can also make lentil loaf which can be eaten cold for days out)
Any soup is filling. (Veg soup is any veg plus stock and herbs or spices, boil until veg is cooked, blend smooth if you prefer smooth soup)

If you want potato (baked, mashed, roasted) use sweet potatoes.
Instead of rice, pasta or potatoes eat a big pile of steamed veg.
Instead of bread use lettuce leaves to wrap your fillings.

Eat when you are hungry, if you wait you'll be too hungry to eat slowly and more likely to binge on the wrong things.
Snack on nuts, raw veg (carrots, swede), fruits (particularly apples)

If you like avocado eat one for lunch with a side salad. The simpler the better.

Good luck

Most of these work with those criteria
http://blog.myfitnesspal.com/11-fifteen-minute-lunches-under-400-calories/