Preheat the oven to 230 C / Gas 8. Place the fish fingers on a baking tray and bake until browned, about 15 minutes.
Slice the buns and place the cheese slices on the bottom half of the buns. Using a large spatula place 3 fish fingers on each bun. Top each with 1 tablespoon tartare sauce and top with top part of the bun. Serve with fries.