Cod in curry sauce

Name: Cod in curry sauce
Ingredients: 2 tbsp sunflower oil; 1 medium onion, finely chopped; 20g/¾oz fresh root ginger, peeled and chopped; 2 garlic cloves, peeled and chopped; 2 tsp medium curry powder; ½ tsp ground turmeric; good pinch dried flaked chillies; 1 lime, juice only; 200ml/7fl oz tinned coconut milk, well stirred; 1 tsp cornflour; 1 tsp caster sugar; salt and freshly ground black pepper; freshly cooked rice, to serve; 1 tbsp sunflower oil; 2 x 140g/5oz thick cod fillets, with skin; pinch ground turmeric