Make the stuffing by putting anchovies, oil, garlic and herbs into a bowl and mix. Add the chopped calamari, breadcrumbs and grated parmesan. The mixture should come together in your hands without being too sticky. Stuff the calamari pockets with the mixture, not too full or they will burst during cooking. Close up and secure the openings with toothpicks. Put olive oil, diced tomato and basil into a wide based pan, set over a low heat and warm through without boiling. Season to taste. Meanwhile, heat a griddle pan until smoking and grill the calamari. Put them into the pan of sauce and cook gently for a few minutes. Serve the calamari in the sauce, garnished with basil leaves and with toasted bread on the side.