Pat it the joint dry and allow the joint to reach room temperature. Preheat the oven to 220°C/Fan 200°C/Gas 7. Rub the joint with a drizzle of oil and generously season with sea salt and pepper. Place the joint fat-side-up on a roasting tray over chopped carrot, onion and celery in the center of the oven. After 15 minutes, reduce the oven temperature to 180°C/Fan 160°C/Gas 4 and add a large glass of liquid (red wine, white wine, or beef/chicken stock all work well). Roast for 12 minutes per 500g, turning the joint halfway through for even cooking. Once roasted to your liking, set the beef aside, loosely covering it in foil after 10 minutes of resting to keep it warm. For desired doneness, aim for 49-51°C for rare, 53-55°C for medium-rare and 57-59°C for medium if using a thermometer. For a little extra, add 450ml of beef or chicken stock to the pan, reduce until thickened, pass through a sieve to remove bones and vegetables. Optionally, enrich the gravy with a cold knob of butter. Rest for a minimum of 20 minutes before carving into thick slices.