Trim the stalk ends from the okra and cut the pods into 1.5 cm (¾ inch) lengths.
Heat 2 tablespoons of the oil in a large deep-sided frying pan or shallow flameproof casserole and fry the okra for 5 minutes. Lift out with a slotted spoon on to a plate.
Add the remaining oil to the pan and very gently fry the onions, peppers and celery, stirring frequently, for 10 minutes until softened but not browned. Add the garlic, spice blend and turmeric and cook for 1 minute.
Pour in the stock and coconut milk and bring to the boil. Reduce the heat, cover and cook gently for 10 minutes. Return the okra to the pan with the sweetcorn, lime juice and coriander and cook for a further 10 minutes. Season to taste with salt and pepper and serve.