1. Finely crush bay leaves and mix with pepper, coriander, and fennel. Transfer spices to a glass dish.
2. Add wine, vinegar, Worcestershire, garlic, rosemary, and olive oil; whisk to combine.
3. Poke London broil all over with a fork and place in marinade. Spoon some marinade over top.
4. Cover and refrigerate, turning occasionally, for 12-24 hours.
5. An hour before cooking, transfer steak to a plate and set aside at room temperature.
6. Transfer marinade to a small pot and bring just to a boil. Set aside.
7. Preheat a grill and on an oiled rack set about 4 inches over glowing coals, grill the meat, turning once.
8. Grill 9-10 minutes on each side, or until it registers 125-130F, on a meat thermometer, for medium-rare meat.
9. Transfer meat to a cutting board and let stand 10 minutes. Cut meat diagonally across the grain into thin slices.
10. Serve with cooked marinade sauce spooned over meat.