Quarter the potatoes and boil for 12 – 15mins until really soft. Then drain, roughly mash and leave to cool a little.
Meanwhile place the kippers into a large shallow container. Pour over enough boiling water to cover then leave to cool. Drain and pull away flakes of fish, taking care to remove all the fine bones. Mix together the fish, potatoes, egg yolk, parsley and season well. Use your hands to shape into 8 patties, then place in the fridge for 30mins to firm up a little.
Beat the remaining egg and place on a plate. Tip the flour and oats out onto 2 other plates and season. Place each fishcake into the flour, and dust away any excess. Then dip in the egg, followed by the oats and coat well.
Heat the oil in a large nonstick frying pan. Add the fishcakes and cook for about 3mins on each side until golden brown all over. Serve with lemon wedges to squeeze over.