Place the haddock (or cod) in a bowl and fill with water just to cover the fish (use as little water as needed). Remove the fish and add the salt and vinegar; stir to dissolve the salt.

Put the fish back into the brine and allow to marinate for one hour at room temperature. (Minimum one hour, but if you leave it too long, it can get too salty.) Afterwards, remove the fish and put it on a rack to dry. 

Peel and cut the potatoes into chunky, thick chips (as seen in the photo above) and put into a bowl of cold water.

Be sure to cover all of the potatoes or they will turn black.

Put the flour and baking soda into a bowl and stir with a whisk; make a well in the center.

Mix the milk and water together in a jug and pour into the dry ingredients.

Whisk into a batter and keep whisking until a thick consistency is formed. It shouldn't be so runny that if falls off the whisk quickly, but not so thick that it doesn't want to drip at all. The batter is a good consistency, when it flows smoothly, but slowly. Pour some into a tray, or plate, where you can batter the fish easily.

No matter how you prepare the chips, dry them well after taking them out of the water.

You have some options when it comes to preparing the chips. You can fry them in the oil where you will fry the fish, then heat them up just before you're finished frying the fish (in the oven or an air fryer). Or you can simply make the chips in the oven or air fryer, or fry them in a separate pot or deep fryer.

If frying, I find it's worth taking the extra step to fry the chips for about 5 or 6 minutes, then remove them from the oil, let the oil heat up again, then add the chips back in to finish cooking. It makes them more crispy and delicious this way.

Pat the haddock fillets completely dry with some paper towel. If they are too large, cut them to the size you desire. Cut a little piece of fish, dip it in batter and fish dressing and fry it in the oil when it's ready. This will test the temperature of the oil and you can taste the fish to see if it needs more salt. However, Dad says it's better to undersalt than oversalt.

Using your fingers, dip the fish into the batter and allow some to drip off before place into the Paxo golden breadcrumbs.

Shake the tray a little to make sure the bottom is completely covered. Sprinkle some fish dressing (from the canister) on top of the fish. Coat the entire filet.

The fish should fry for about 3 minutes each side. Use a slotted skimmer and another tool to gently turn the fish over. If you've done the batter and breading correctly, it will not come off the fish.

Use the slotted skimmer to take out the fish (allow the oil to drip off before placing on a paper towel lined plate or tray.

Continue with the rest of the fish. When the fish and chips are fried, it's time to serve them, don't wait!

Break the fish into pieces, and whatever you do, don't use a knife and fork! Fish and chips is finger food!