Heat the oven to Gas Mark 4, 180°C (350°F).
Heat the oil in a 3 litre flameproof casserole dish over a medium heat and brown the sausages. Remove to a plate. Add the bacon to the casserole and allow to cook until golden. Stir regularly. This will take about 5 minutes. Using a slotted spoon, transfer the bacon to the plate with the sausages.
Turn the heat down to medium, add the onions to the juices left in the casserole. Allow to cook until the onions have softened, about 10 minutes. Turn from time to time. Add the garlic and cook for another minute. Then add in the tomatoes, tomato purée and water. Bring to a simmer and add in the sausages and bacon along with the thyme sprigs, bay leaves, a little salt and lots of black pepper. Stir to combine.
Cover with a lid and place in the oven for an hour. Remove from the oven, discard the bay leaves, stir through the beans then sprinkle the breadcrumbs and parsley over the top. Return to the oven, uncovered, and bake for a further 20 minutes.