Combine the mince with the stuffing mix and 1 tbsp water, then season. Spoon the mixture over the cranberry sauce, pressing down slightly, then lay the chipolatas on top in a line across the middle of each pastry half. Brush some of the egg along one edge of each pastry half, then fold up and over the filling, and press to seal to make two long sausage rolls. Turn them so the seams are underneath. Cut both into eight pieces (you should have 16 in total), then transfer to the tray. Brush with the remaining egg, then press a sage leaf on top of each roll. At this stage, you can freeze the rolls on the tray. Transfer to a container to keep frozen for up to two months.