Add the olives, capers, garlic and anchovy to a food processor. Add 1/2 cup olive oil and black pepper to taste. Process to form a silky paste with small pieces of olive and capers remaining, 15 to 20 seconds. Drizzle in more olive oil as needed. Remove the tapenade from the carafe, then drizzle with olive oil and set aside.
Drizzle the center of each of 4 large circles of parchment paper with some olive oil, then sprinkle with salt and pepper. Top each piece with a thin layer of fennel and some leeks. Top each with a dollop of the olive tapenade and 2 to 3 lemon slices. Lay the fish on top of the lemon slices and sprinkle with salt and pepper. Fold the parchment in half to cover the fish, then crimp the edges shut, being sure to cover the corner of each previous fold. When you are halfway through folding, add 1 tablespoon of white wine to each packet, then continue to fold until the entire package is formed and closed. Place each packet on a baking sheet.
Bake the fish for 8 to 10 minutes. Remove from the oven, then place each packet on a plate. Cut open the top of the paper to expose the fish. Garnish each fillet with the Calabrian chiles and basil. Serve immediately.