Grill the sausages, at the same time softening the onion in a large saucepan. When the sausages are cooked, remove them from the grill and drain on kitchen roll. Put the sausages in the saucepan with the cooked onion. Add the tomatoes and baked beans and crumble in the Oxo cube. Stir gently and heat through. Serve with mashed potato and a green vegetable.