Preheat oven to 180°C. In a small bowl mix together oregano, honey and mustard and season with sea salt and cracked pepper.
Place the lamb into a roasting tray and baste with the honey mustard mixture, ensuring the meat is completely covered. Loosely cover with foil. Place in the middle of the oven and cook for 1 hour.
Remove foil (don’t discard), baste and cook for 20 minutes more.
Remove from oven, again loosely cover with foil and rest for 15 minutes before carving.