Combine mince, egg, breadcrumbs, tomato sauce, half the Worcestershire sauce and the garlic salt in a bowl; shape mixture into 12 rissoles.
Heat half the oil in a large frying pan over medium heat. Add rissoles and cook for 3 minutes on each side or until browned; transfer rissoles to a plate lined with paper towels.
Heat remaining oil in same pan; add onion, garlic, mushrooms and bacon. Cook, stirring, for 5 minutes or until bacon is crisp. Stir in flour and cook for 2 minutes or until lightly browned. Gradually stir in stock and remaining Worcestershire sauce; bring to the boil and simmer for 1 minute.
Add rissoles and simmer for 3 to 4 minutes or until rissoles are cooked through and gravy has thickened slightly. Serve rissoles topped with gravy.