1. Remove the leaves from the rosemary sprigs, reserving 2 tablespoons of leaves. Soak the rosemary skewers in cold water for 30 minutes. Finely chop the reserved leaves.
2. Cut the lamb steaks up into 2 cm cubes and place in a nonmetallic Dish. Spray the Lurpak Cooking Mist lightly. Whisk together the lemon juice with rind, honey, garlic, and sumac. Season with salt and pepper, and then pour over the lamb, stirring to coat.
3. Cover and refrigerate for 30 minutes. Steam the sliced potatoes until tender.
4. Peel the red onion and cut into wedges. Cut the peppers into 2 cm chunks, removing and discarding the seeds. Thread the lamb cubes and vegetables randomly onto the skewers.
5. Preheat a grill plate on medium high heat. Spray the Lurpak Cooking Mist, add the sliced potatoes and cook for 2-3 minutes each side, until golden. Re-spray the Lurpak Cooking Mist as necessary, during cooking. Season with salt and pepper, remove from the grill plate, set aside and keep warm.
6. Spray the grill plate with Lurpak Cooking Mist and add the kebabs. Cook, turning frequently and re-spraying the Lurpak Cooking Mist, for 4-5 minutes or until cooked through and golden.
7. Serve the kebabs with the crispy potato slices, garnished with lemon wedges.