Preheat oven to 200 C / Gas 6. Lightly grease a loaf tin with oil.
Place bread and milk in a small bowl. Press bread with a fork to soak up the milk.
Combine lamb, egg, garlic, thyme, Worcestershire sauce, lemon zest, coriander, basil, rosemary, salt and pepper in a medium bowl. Add soaked bread; discard the leftover milk. Mix with hands until well combined. Transfer meatloaf to the prepared tin.
Combine ketchup and mint; spread evenly over the meatloaf. Drizzle with balsamic vinegar.
Bake in the preheated oven until no longer pink in the centre, about 35 minutes. Remove and let cool for 5 minutes before serving.