For the marinade: Combine the garlic, bay leaves, carrots, celery, onions and wine in a large bowl or container. Add the beef; cover and let sit in the refrigerator at least 4 hours or overnight. (This is a really important step: it makes a huge flavor difference.)
For the stew: Remove the beef from the marinade. Strain the veggies and bay leaves from the marinade and discard. Reserve 2 cups of the marinade.
Preheat the oven to 350 degrees F.
Coat a large, wide pan or Dutch oven with olive oil and bring to medium-high heat. Sprinkle the beef with salt and toss with the flour; do not flour the beef until you're ready to brown it. Add the flour-coated beef to the hot pan, but be sure to not crowd the pan; you will need to work in four batches. Brown the meat well on all sides, 12 to 15 minutes. Remove from the pan to a baking sheet.
After the first two batches, deglaze the pot with 1/2 cup of the reserved marinade, scraping up any browned bits. Drain the liquid into a small bowl. Add more olive oil to the pan to coat and cook the remaining two batches of meat. Add the meat to the baking sheet. Deglaze the pan with 1/2 cup marinade, scraping up any browned bits.
Add the bacon and cook until it gets brown and crispy, about 5 minutes. Toss in the mushrooms, carrots, celery, garlic and onions, and season with salt. Cook until the mixture starts to soften and becomes very aromatic, about 10 minutes. Add the tomato paste and cook, 1 to 2 minutes. Add the remaining 1 cup marinade and deglaze the pan, stirring up any browned bits, 1 minute. Add the beef. Stir to combine and cook until the wine has reduced by half, 1 to 2 minutes. Add enough of the beef stock to just cover the surface of the beef. Toss in the bay leaves and thyme bundle. Cover the pan, bring the liquid to a boil and put in the oven.
Cook the beef for 2 hours. During the last hour of cooking time, add the potatoes. Cover the pan with the lid and put the stew back in the oven to cook for an additional hour.
Remove the pot from the oven and skim off any excess grease from the surface of the stew. Garnish with the chives and serve with crusty bread to sop up all the sauce.