Brush the lamb chops lightly with oil. Season with salt and pepper, and sprinkle with the rosemary. Preheat the barbecue to hot then add the lamb.
Cook on one side for 2-3 minutes until the first sign of moisture appears. Turn lamb once only. Test the lamb chops for degree of doneness with tongs. Remove lamb from heat, loosely cover with foil and rest for 3 minutes before serving.
Toss together the lettuce, watercress, avocado, cucumber and pepitas. Combine the lemon juice and olive oil and season to taste. Drizzle over salad and gently toss to combine, serve with the lamb.