Place the lamb in a shallow dish. Mix together the oil, lemon zest and juice and seasoning. Drizzle the mixture over the lamb and marinate at room temperature for 15 minutes. Meanwhile mix together the dressing ingredients. Heat the barbecue, grill or griddle pan to high and cook the lamb for 3-4 minutes on each side until cooked to your liking, turning once.
Serve with baby potatoes and a mixture of peas, green beans and broad beans. Drizzle over a little of the dressing. Gently sautéed, chopped cherry tomatoes are a nice addition.