Place carrots and beetroot one tin at a time into a blender and blend until smooth. Heat olive oil in a frypan over medium heat. Cook and stir garlic and onions until onions are translucent. Stir in pureed carrots and beetroot then add the bay leaf, Italian seasoning and red wine vinegar. Cover and cook until the sauce begins to boil. Remove lid and reduce heat to low. Simmer for up to 4 hours, or at least 30 minutes.