Cook the beef in the oil in a large sauce pan over medium-high heat until browned on all sides before setting aside and draining off all but 1 tablespoon of the grease.
Add the onion and cook until tender, about 5 minutes. Add the garlic and cook unitl fragrant, about a mintute.
Add 1/2 cup of the broth and deglaze the pan by scraping any brown bits up from the bottom of the pan as the broth sizzles before adding the remaining broth, stout, rosemary, thyme and bay leaves.
Bring to a boil, reduce the heat and simmer, covered, until the beef is almost falling apart tender, about 2-3 hour, OR transfer to a preheated 350F/180C oven and roast, covered, until the beef is tender, about 2-3 hours, OR transfer to a slow cooker and cook on low for 6-10 hours or on high for 3-5 hours.
Add the potatoes and carrots and cook until tender, about 15 minuites.
Add the Worcestershire sauce and fish sauce before seasoning with salt and pepepr to taste.