Rub the pork skin with a little oil and salt, and if possible leave to soak overnight. With a knife make a shallow incision down the centre of the belly, cutting towards but not through the rind, and make two pockets into which you place the stuffing. Roll the joint so that the two long ends meet around the stuffing, andtie firmly at 2.5cm intervals. Give the rind a second rubbing with salt and place on a rack in baking dish. (Tim is important if you want every square centimeter of crackling, as the rind will never become crisp at the point of contact with the baking dish.} Bake in a very hot oven 230C (450F) for 30 minutes, then reduce to moderate 180C (350F) for a taififer 1-1/4 hours. Potatoes may be baked around the joint. Remove to a heated serving dish. Pour off excess fat and make gravy. If you like, stir in one tablespoon of chunky marmalade.