Preheat oven broiler.
Combine all meatball ingredients in a large bowl. Shape mixture into small meatballs and place in an ovenproof dish. Grill beneath the broiler for 10 to 12 minutes, or until lamb is cooked through, turning over halfway through cooking. Reserve.
Assemble sandwiches by placing garnishes in each pita round. Add lamb meatballs, fresh mint and sprinkle with lemon juice. Close pitas tightly.