Preheat the oven to 180°C bake and line a roasting dish with baking paper.
Add the beef mince, sausage meat, onion, carrot and courgette if using, breadcrumbs, Worcestershire sauce, beef stock powder, mixed herbs, egg, ¼ cup tomato or BBQ sauce, salt and pepper to a large bowl.
Using clean hands or a sturdy spoon, mix until everything is evenly combined without overworking the mixture.
Transfer to the prepared roasting dish and shape into one large loaf. Alternatively, divide into two smaller loaves.
Spread the remaining ¼ cup tomato or BBQ sauce evenly over the top.
Cover loosely with foil and bake for 40 minutes.
Remove the foil and return to the oven for a further 10 minutes, or until golden on top and completely cooked through.
Allow the meatloaf to rest for 5–10 minutes before slicing and serving.