Preheat oven 185°C. Combine all the stuffing ingredients in a bowl and set aside. Open the butterflied leg of lamb out on your chopping board, skin side down. Trim sinew, being careful not to cut any holes in the meat. Season with salt and pepper, spread the stuffing mixture over the lamb leaving a 2 cm border. Tightly roll the lamb and tie with kitchen twine at 2 cm intervals. Transfer to a casserole dish and season generously with Simon Gault Italian seasoning. In a saucepan, melt the butter then add the onion and garlic and sauté whilst stirring over a medium heat until the onions are soft. Add the Simon Gault Italian Seasoning, celery, tomato paste and cook for a further two minutes then add the cranberry juice, Gault's Lamb Stock (with water), honey, cracked black pepper and dried cranberries. Transfer to the casserole dish, pouring the sauce around the base of the lamb. Place the uncovered casserole dish in the oven and cook for approximately 1 hour or until the internal lamb temperature reaches the desired temperature, medium 65-68°C or for well-done 75°C. If you are without a temperature thermometer, a general rule of thumb is to cook lamb for an hour for every kg at 185°C.