Preheat the oven to 180C/350F/Gas 4.
To make the tapenade, place the anchovies, garlic, olives, lemon juice and four tablespoons of olive oil in a food processor and blend to a coarse mixture, don't make it too smooth. Add the basil and parsley and pulse gently to combine. Season to taste.
Take the tapenade mixture and spread over one side of each plaice fillet. Roll up the fillets from the head to the tail end and fix with a small skewer or cocktail stick. Put the fillets into a baking dish and pour the wine over the fish.
Place a piece of generously buttered parchment or baking paper directly on top of each fillet, butter side down, and bake for 20 minutes.
Meanwhile, place the tomatoes on a baking tray and coat with the oil. Roast until the skins start to split, about 10-15 minutes.
Serve the baked fish with the tomatoes. Drizzle any cooking juices over the fish.