In remaining oil on medium-high heat add leek, onion and garlic, and cook, stirring, for 4-5 minutes or until softened. Add harissa, cinnamon, star anise and orange zest, and cook, stirring, for 2-3 minutes or until fragrant. Add orange juice and white wine, and bring to the boil, Cook for 2-3 minutes or until wine mixture is reduced by half. Stir through apricots, dates, chick peas, tomatoes and stock, and bring to the boil, Return lamb to the casserole, then cover and transfer to oven. Cook for 3 hours 30 minutes or until meat begins to flake away from the bone.