Salt and pepper the cubed beef and let sit at room temperate with the bacon for 20 minutes.
Once ready, add the bacon to a dutch oven and cook until crispy. Remove to a plate with a slotted spoon, then remove the excess bacon fat, leaving about 1 tbs behind. Brown the beef on all sides, making sure not to crowd the pan. Remove to a plate and set aside.
Add a touch of olive oil and the carrots, celery and onion. Cook until softened (about 6 minutes), then add the garlic and cook until fragrant (about 1 minute).
Add the flour, stirring to make sure all the raw white flour bits soak in to the veggies. Cook for about a minute, then add the tomato paste, breaking up with your spoon and cook for 2–3 minutes or until it becomes a deeper red.
Deglaze with the guinness, making sure to scrape up any brown bits. Add the beef stock, water, worcestershire, herbs, beef and bacon to the stew. Stir and bring up to a boil. Cover and lower the heat to a simmer and cook for 3 hours, stirring occasionally. Then, bring the heat up slightly and cook, partially covered, for another hour or until the beef is fall apart tender and the stew is your desired consistency. Now fish out the stems and bay leaves. Add more fresh chopped parsley for serving.