Combine the oyster sauce, soy sauce, sugar, rice wine and 4 tbsps water in a small bowl. Stir and set aside.
Put the oil into a wok or a heavy non stick lidded frying pan and set over a medium high heat. When the oil is hot add the shallots, ginger, garlic and chillies. Stir rapidly for a minute then add the bean sauce and stir once.
Add the curry powder and stir once, then the curry leaves and prawns. Stir rapidly a couple of times then add the oyster sauce mixture and stir.
Cover, reduce the heat to low and cook for about two minutes or until the prawns are just cooked through. Remove the lid, increase the heat to medium high then stir once or twice. Check the seasoning and serve.