Put the diced potatoes in a large pot and cover with cold water by 2 inches. Salt the water generously. Bring to a simmer and cook until you can pierce the potato with a paring knife, 6 to 8 minutes. Drain in a colander.
In the meantime, bring a small pot of water to a boil. Carefully lower the eggs into the water and simmer for 13 minutes. Transfer the eggs to a bowl of ice water. When the eggs have cooled, peel and dice them. Set aside.
While the potatoes are cooking, make the dressing. In a large bowl, whisk together the sour cream, mayonnaise, vinegar, mustard, Worcestershire, hot sauce, garlic, 1 1/2 teaspoons salt and pepper to taste. Add the still-warm potatoes to the bowl of dressing and toss. Set aside to cool completely, about 20 minutes.
Add the bacon strips to a large skillet and turn the heat to medium. Stir periodically and cook until browned and crisp, about 10 minutes. Transfer the bacon to a paper-towel-lined plate.
When the potatoes are cool, gently stir in the eggs, bacon, avocado, tomatoes, scallions, blue cheese and shredded lettuce. Taste and add more salt and pepper if desired.