In a bowl place 2 teaspoons mint marinade, add the Greek yoghurt and the diced cucumber and stir, place in serving dish and sprinkle with coarse black pepper and set aside in refrigerator.
Place the remainder of the mint marinade into a large plastic bag, add the lamb steaks and toss to coat, refrigerate for 30 minutes.
Place steaks in a baking tray (spoon over red wine if using) cook in the preheated oven for 30-35 minutes, or place on BBQ turning after 15 minutes. Serve with cucumber dressing, potatoes and peas or salad.