Blanch the cauliflower for one minute and trim the rainbow chard. Roast the cauliflower, broccoli and chard with a sprinkle of turmeric and a dash of oil for 20 minutes.
Sprinkle 1 teaspoon of turmeric all over the fish and season well.
Heat the grill to high heat and cook the fish for about three minutes on each side. Leave to rest.
Quarter the potatoes and add them to a pan of hot water. Cook the potatoes until tender, drain and allow to cool.
Mix the dressing ingredients together until smooth and toss all the ingredients, except for the fish, until well coated.
Transfer to a bowl, top with the fish and serve with roasted peppers, toasted sesame seeds and watercress.
