Preheat oven to 200°C.
Heat the oil in a large frying pan, over medium-high heat. Add the lamb mince and cook for 7-8 minutes or until brown, stirring regularly. Add the onion and carrot, cook for further 5 minutes.
Stir in the Knorr Beef Stock Pot, water, tomato ketchup and Worcestershire sauce. Bring to the boil and simmer for 5 minutes then add the peas.
Pour lamb mixture into a 25 cm deep dish, and top with mashed potatoes.
Sprinkle with the grated cheese, and bake for 20-30 minutes or until golden and bubbling.
Leave to stand for 10 minutes before serving.