Method:
1 Heat oil and 20g butter in a frying pan over medium heat add perch and lemon juice and cook for 3-4 minutes each side or until cooked through.  
2 Place potatoes in a microwave-safe bowl, cover and microwave on High/100% for 4-5 minutes or until potatoes are tender.
3 Heat oil in a frying pan over medium heat add 20g butter and leek and cook for 3-4 minutes or until leek softens and caramelises. Combine diced potato, olives, chives and leek in a bowl.
4 Spoon the potato salad onto a plate, top with perch fillet and pour over the pan juices. Serve.