Put the fennel seeds, garlic, sage, thyme and oil in a bowl and mix together.
Using a sharp knife, make 4 mm (½ in) deep score lines into the pork skin, spacing the score lines about 3 mm (1.8 in) apart. Take the fennel seed mixture and rub it all over the pork. Transfer the pork to a dish and season all over with salt and pepper. Wrap the dish really well in p