Heat the oven to gas 5, 190°C, 375°F.
Lightly oil two baking trays. Using a sharp knife, make three slashes on one side of each fish. Place the sea bass on the baking trays.
For the salsa verde, mix together the finely chopped parsley, basil, anchovies, capers, green chilli, garlic, lemon juice, olive oil and seasoning, mix well. Spoon a teaspoon of the salsa verde into each of the slashes. Place the fish in the oven and roast for 10 minutes. Rotate the trays to ensure even cooking of the fish and roast for a further 5 minutes.
Serve the remaining salsa in small individual bowls alongside the roasted fish.