Put the pepper halves in a roasting tin and cook in a preheated oven, 180°C (350°F), Gas Mark 4, for 20 minutes, until the skin has blackened and blistered. Cover with damp kitchen paper and set aside. When the peppers are cool enough to handle, peel off the skin and chop the flesh. (Leave the oven on.)
Mix together one of the chopped peppers, the rice, garlic, tomatoes and parsley. Season to taste.
Put the lamb on a board and make a horizontal incision, almost all the way along, to make a cavity for stuffing. Fold back the top half, spoon in the stuffing and fold back the top. Secure with skewers.
Cook the lamb for 1 hour, basting frequently and adding the artichokes and other pepper for the last 15 minutes of cooking time. Slice the lamb and serve immediately with roasted new potatoes, if liked.