Follow this https://www.bbcgoodfood.com/recipes/2239/ultimate-fish-cakes but don’t bother with horseradish for the sauce. Use decent mayo.
Cook in veg (sunflower or olive) oil, doesn’t need anywhere near as much as it says. 2 tbs max, add 1 tbs for first side and another when you turn them over. If they are thick it helps to make a bit square and stand on their sides to make them crispy.
Serve with massive mixed green salad.