Heat a grill over medium high heat. Split the lobster tail in half, sprinkle with Old Bay and dot with butter. Place on grill, shell side down, and grill for 8-10 minutes. Remove from the shell and roughly chop.
Spread the garlic bread spread on the bun and lightly toast on the grill.
Smear the mayonnaise on one side of the bun and layer the bacon, lettuce, tomato and lobster on top. Serve.