1.Heat the oven to 200C. Put the stuffing, pigs in blankets and turkey in a lidded ovenproof dish, cover and reheat in the oven for 10 mins. Stir the gravy to loosen, then pour into a shallow bowl. Soak one slice of bread in the gravy, flipping over once, until most of the gravy has been absorbed. If the gravy is very thick, you can spread it over both sides instead. Heat the sunflower oil in a non-stick frying pan over a medium heat and fry the soaked bread on both sides until brown and crisp. Transfer to a plate and set aside.
2.Spread the mayonnaise over one side of each of the two remaining bread slices, and butter the other sides. Spread the mustard over the butter on one of the slices, then spread the cranberry sauce over the butter on the second slice. Season both slices lightly. Lay the mustard-topped slice in the pan, mayonnaise-side down, then spoon over the stuffing and a slice of turkey. Top with the gravy-soaked bread slice, the pigs in blankets, the second turkey slice and the cabbage. Finally, sandwich with the second bread slice, cranberry-side down. Fry until the underside is golden, then carefully flip over and repeat. Cut in half and serve.