Brush English muffins with butter; set aside. In a bowl, combine the crab, shrimp, 3/4 cup cheese, celery, olives and parsley. Combine the mayonnaise, lemon juice, mustard and Worcestershire sauce; pour over seafood mixture and toss to coat.
Place a rounded 1/4 cupful of the mixture on each muffin half; sprinkle with remaining cheese. Place on a baking sheet. Broil 4-6 in. from the heat for 3-4 minutes or until heated through and cheese is melted. Serve immediately. Yield: 4 servings.