Heat the oil in a large casserole dish that is suitable for the oven. Add the sausages and fry them until they are browned on all sides. Take out and put them to the side.
Add the onion, garlic and bacon and fry until softened. Put the sausage back in the pan along with the chopped tomatoes, spices, beer, herbs and sugar. Season with salt and pepper. Bring to the boil, cover and put in the oven (or continue cooking on the stove). Cook for about 40 minutes.
Remove from the oven, take out the sausages and cut them into three pieces each, then put them back in the casserole and add the beans. Cook for another 10 minutes uncovered until the beans are heated through and the juices start to thicken. Garnish with chopped parsley and serve with garlic bread or creamy mashed potatoes.