Preheat the oven to 220°C.
Deseed the chilli, remove its vein and chop finely. Peel the garlic and chop up finely. Chop the rosemary leaves.
Using a pestle & mortar crush the garlic, chilli, two-thirds of the rosemary and fennel seeds together until you get a paste. Season to taste with coarse salt and ground pepper. Crush again.
Use a sharp knife to make small incisions all over the meat. Rub with the oil and some salt then the paste, massaging it into the slots with your fingers.
Sprinkle with the remaining rosemary and place the lamb on a rack over a baking tray.
Cook for 20 minutes in the oven then lower the temperature to 190°C. Pour the wine into the baking tray with some added water (underneath the lamb). Roast for about 90 minutes depending on how well cooked you like your lamb. During cooking regularly baste the meat with the sauce and add more water if needed!
When the lamb is cooked to your liking, remove it from the oven, cover and let it rest for 20-30 minutes.