Mix the potato, spring onions, horseradish and mackerel in a large bowl. Split into 6-8. Mould into your fish cake shape. Dust in the flour, dip into the egg then cover in milled flaxseed. Add to a hot pan cooking for 2-3minutes on one side. Flip and cook on the other for a further 2-3 minutes. Enhoy immediately whilst hot or store in the fridge perfect for lunch the next day. Serve with your fave salad or vegetable. 1 serving is 2 fishcakes.