In a small bowl, combine the butter, mayonnaise, bacon and garlic.
Spread over cut sides of bread.
Wrap on a large piece of heavy duty foil (about 36 inches X 18 inches).
Grill, covered, over medium heat 4 to 5 minutes on each side.
Unwrap and separate bread halves.
Sprinkle with cheese.
Grill 5 minutes longer or until cheese is melted.