1) Bring a saucepan of water to the boil and add the potatoes. Turn down to a simmer and cook for 10-12 mins until tender.
2) Drain and mash then set aside.
3) Meanwhile, cook the fish. Heat a shallow pan of water to a simmer. Add the lemon juice and the fish. Poach for 5 mins or until fish is just cooked through.
4) Remove from the water,and remove any skin. Flake into large chunks.
5) Add the lemon zest, herbs, spring onions, tartar sauce, and fish to the mashed potato.Combine all the ingredients.
6) Divide into 12 and shape into cakes. Refrigerate for 30 minutes.
7) Put the eggs, flour and breadcrumbs on three separate plates.
8) Dip each of the fish cakes in the flour, then in the egg and finally the breadcrumbs, making sure they are well coated.
9) Repeat with the remaining fish cakes.
9) To cook, heat the grill to medium. Brush the fish cakes with the oil and grill for 4-5 mins each side until golden.