Soften onions, garlic and other veg in vegetable oil. Add tinned tomatoes and tomato paste and simmer until cooked.
Add kidney beans 5 minutes before the end. Season Melt butter and add flour gradually to form a roux.
Add milk gradually over a low heat constantly stirring until sauce thickens.
Add grated cheddar and season.
In an oven-proof dish start with a layer of the vegetable mixture, followed by some lasagne sheets, another layer of veg followed by cheese sauce, then another layer of lasagne sheets followed by the remaining veg and then the remaining cheese sauce.