Cook the potatoes, mash them and allow them to cool.
Cook the fish and the onion in the milk as per its instructions, drain the milk, and leave it to cool.
In a bowl gently mix the potato, onion, fish, beaten egg, sweetcorn, flour, herbs, salt and pepper and the cheese.
Make the mixture into the desired size fishcakes and put into the fridge to chill for at least 1 hour.
I push the mixture into a 2-inch pastry cutter as a mould (the sort used to cut out mince pies) onto grease-proof paper.
After chilling, heat the oil up to fry either in a frying pan or a deep-fat fryer. Fry until golden brown and sizzling. Mine takes about 6-8 minutes.
Serve immediately with sweet chilli sauce and salad.