Preheat oven to 220°C.
Deseed and chop the chilli. Peel and chop the garlic. Chop most of the rosemary leaves.
Using a pestle and mortar crush these roughly, then add the fennel seeds and season with coarse salt and ground pepper. Crush it into a coarse paste with the oil.
Make 1 cm deep slits in the lamb, then rub the paste all over the meat. Sprinkle with the remaining rosemary and place it in a roasting tin.
Put it in the oven for 20 minutes, then lower the temperature to 190°C.
Pour the wine into the tin and some water, then roast for about one hour, depending how well cooked you like your lamb.
Baste the lamb a few times during cooking and add more liquid (wine or water), if needed.
When the lamb is cooked through to your liking, remove it from the oven, cover with foil and let it rest for 15 minutes.
Meanwhile, make the gravy using the cooking juices, by adding a little cornflour, stock/wine/port and a spoonful of redcurrant jelly or cranberry sauce. Heat it up in the tin and reduce it to a thick sauce by stirring it with a wooden spoon and scraping up the sticky bits.
Serve the lamb with vegetables and the gravy.