Preheat the oven to 190°C. Heat the olive oil in a big pot or frying pan over a medium heat. Add the onion and cook for a few minutes until softened. Add the beef, bacon, garlic, carrots and mushrooms and cook until the beef has browned. Pour in the red wine and bring to a boil before adding the chopped tomatoes, salt and pepper, oregano, basil, stock cube, chilli flakes and tomato purée. Simmer for half an hour.
While the tomato sauce is cooking make the white sauce. Melt the butter over a medium heat and whisk in the flour. Once you have a smooth paste gradually pour in the milk while whisking. Add the mustard, cheeses, nutmeg and a sprinkling of salt and pepper. Cook for 5-10 minutes until thickened. Remove from the heat.
You're now ready to assemble your lasagne. Spread a couple of spoonfuls of meat sauce in the bottom of a baking dish, top with lasagne sheets and a spoonful of white sauce. Repeat the process until you've finished the meat sauce and make sure to finish with a final layer of white sauce. Top the whole thing with grated cheddar, cover with foil and cook for 45 minutes removing the foil half way through cooking.