Add your beef to a frying pan on a medium to high heat with olive oil and brown.
Once you've browned off the meat, add to your slow cooker. Next add the diced onion, celery, carrot and garlic followed by the beef stock, red wine vinegar, Worcestershire sauce, tomato puree and chopped tomatoes. Mix well until everything is combined.
Add bay leaves, oregano, mixed herb, thymes, salt and pepper. Mix well and then put the lid on your slow cooker.
Cook on high for 3-4 hours, until the sauce starts to thicken OR on low for 7-8 hours.
Serve with gluten free pasta and enjoy.