In a 5- to 7-quart pot over medium heat, cook the bacon, sausages, and ½ cup of the potatoes until the sausages and bacon are browned. (Use a spoon to break up the sausages as you go.) Add the garlic, onion, celery, carrots, bell pepper, and herbs. Cook, stirring, until the vegetables are tender and the onions translucent, about 10 minutes. Increase the heat to medium-high and add the bottled clam juice, stirring to scrape any browned bits off the bottom of the pot. Add the tomatoes in their liquid and the remaining ½ cup of the potatoes. Bring the chowder to a simmer. Add Old Bay and season with salt and pepper. Simmer (don’t boil) until the potatoes are tender, 15 to 20 minutes. Add the clam meat with its juices to the chowder just before serving. Serve hot.