Pat it the joint dry and allow the joint to reach room temperature. Preheat the oven to 220°C. Rub the joint with a drizzle of oil and generously season with sea salt and pepper. In a hot pan, sear the joint fat side down for 3 mins or until the fat becomes beautifully crispy and golden. Sear the remaining sides briefly, allowing the meat to reach a lovely brown colour. Place into the hot oven for 15-20 minutes and baste once the 20 mins is up. Reduce the oven temperature to 160°C and cook for a further 30 mins per kg or until cooked. Use a meat thermometer and aim for 49-51°C for rare, 53-55°C for medium-rare and 57-59°C for medium. Allow to rest for 20 minutes before carving. Enjoy.