Pre-heat the oven and place the sausages on a baking tray before placing in the oven- cooking until they are light brown and cooked through
Finely chop the onion, slice the peppers and peel and quarter the potatoes
Fill a large pan with water and bring to the boil before adding the potatoes and cook until soft. Remove from the heat and drain
In a large casserole dish or frying pan add the onion and peppers and cook gently, stirring occasionally to avoid sticking as the onions caramelise- about 10 minutes
Add the chopped tomatoes and cook for 5 minutes
Add baked beans and drained kidney beans & butter beans and cook for a further 5-10 minutes
Whilst the casserole is cooking, mash your potato, adding a small amount of butter and seasoning to your taste. For smoother potato add a splash of milk (or use a potato ricer instead of a masher for a super smooth texture)
Chop the sausages into bite-size pieces or leave whole, add to the casserole, stir and serve