In a food processor, blend together the first 8 ingredients except the pork until you have a fine paste. If it appears too dry, add a little water. Remove the rind from the pork and set aside. Rub the pork all over with the paste, cover and refrigerate overnight turning the pork from time to time. Preheat the oven to 150?C/300F/gas mark 2. In a heavy casserole dish heat the butter until foaming, add the onions and fry them until they take on a little colour. Remove the onions and set aside. In the same casserole dish, add the pork and any marinade and fry on all sides until brown. Return the onions to the pan together with the sage, prunes and Guinness. Bring to the boil, cover and place in the oven for 3 hours. Remove the meat to a serving dish carefully. You may remove the bone if you wish, as the meat should fall off the bone. Boil the remaining cooking juices until they have attained a coating consistency. Pour over the pork and serve immediately. Per serving: 642 Calories (kcal); 59g Total Fat; (79% calories from fat); 5g Protein; 29g Carbohydrate; 120mg Cholesterol; 3777mg Sodium Food Exchanges: 0 Grain(Starch); 0 Lean Meat; 4 1/2 Vegetable; 0 Fruit; 11 1/2 Fat; 0 Other Carbohydrates Converted by MM_Buster v2.0n.