Saute the beef and bacon in a little oil. Drain off the excess liquid. Remove the meat anmd set aside. Add the butter to the pan, and melt. Stir in the flour to make a roux. Gradually stir in the stout. Place the meat and the small onions (peeled) in a deep casserole dish, and season with the salt, pepper and herbs. Crush the garlic and add to the ingredients. Sprinkle the sugar on top, and pour in the sauce. Cover and place in the oven. Cook very gently for up to 3 hours at 150ºC . Check occasionally. If the casserole seems to be drying a little, you can add more stout. Remove from the oven and mix in the vinegar. Serve with lots of boiled potatoes to sop up the sauce.