1. Mix all the marinade ingredients together in a bowl. Add the fish and coat well with the marinade. Cover and leave to marinate in the fridge for 1 hour.
2.To make the raita, stir the yogurt, cucumber and mint together and season. Cover and chill until ready to serve.
3. Brush a hot non-stick griddle pan with oil or heat the oil in a large frying pan. When the pan is hot, lift the fish from the marinade and griddle or fry in 2 batches for 5-8 minutes each side until slightly charred, brushing with the marinade to keep moist.