Preheat oven to 250C. Cook potatoes in a saucepan of boiling salted water until parboiled (3-5 minutes). Drain, then scatter over base of a 20cm x 30cm oiled baking dish. Top with swordfish, spoon tomato over and scatter with golden shallots, olives, garlic, anchovies and thyme. Bake until swordfish is cooked through (20-25 minutes). Serve immediately, drizzled with extra-virgin olive oil, with lemon wedges to the side.