Arrange tomatoes on a platter. Toss fennel in a bowl with a few tablespoons of the creamy garlic dressing and season with salt and pepper. Mound the fennel in the middle of the platter on top of the tomatoes. Sprinkle with the herbs, cheese and olives and drizzle with some more of the creamy garlic dressing.
Combine mayonnaise, vinegar, lemon juice, mustard and garlic in a blender and blend until smooth. Slowly add the olive oil until emulsified and season with salt and pepper to taste.