Roughly chop the sage and rosemary and combine with the garlic, fennel seeds and half the oil in a small bowl.
Place the pork on a chopping board, skin-side up, and score the rind at 2.5 cm (1 inch) intervals (the easiest way of doing this is with a Stanley knife). Turn the meat over, skin-side down, and season with salt and pepper. Rub the herb mixture all over the flesh. Roll the pork up and tie it tightly with string. Rub the skin all over with the remaining oil, then a generous amount of salt.
Roast in a preheated oven, 220°C (425°F), Gas Mark 7, for 20 minutes, then reduce the temperature to 160°C (325°F), Gas Mark 3, and roast for a further 1½ hours. Leave the meat to rest for 10 minutes before carving and serving. The Braised Black Cabbage & Borlotti on