Line the insides of the loaf with the slices of Parma ham overlapping them and leaving an inch or so overhanging at the top. Arrange the remaining ingredients inside the prepared shell, using a quarter of them at a time, so that you have 4 layers of each: for example, use a quarter of the peppers, followed by a quarter of the mozzarella and so on until you reach the top of the loaf. Fold the overhanging edges of Parma ham back to the top of the filling to enclose it. Place the lid firmly on top and wrap tightly in cling film. Chill for 2 hours, or overnight if not using straight away.