Pour in the stout and let it bubble for 5 mins, scraping up any sticky bits from the base of the pan. Return the beef and any resting juices to the pan, add the thyme and bay, then add the Worcestershire sauce and stock. Bring to a simmer, stirring well, then cover, transfer to the oven and cook for 2 hrs 30 mins-3 hrs, stirring once or twice, until the beef is fork-tender.
