Good to hear someone has been to your feeding station, but boiled potatoes aren’t really a very good diet for hogs. They really need something with protein in it. The recommended foods are cat/dog food, cat/kitten biscuits or hedgehog food from a reputable source. (But not dried mealworms as they have the wrong Calcium/Phosphorous ratio and can cause bone problems, particularly to hoglets – which are around now.) None of this, of course, totally replicates what they would find in the wild – beetles, earthworms, caterpillars, etc. but, the the best we have at present. You may not want to go to too much expense, especially as you aren’t certain, yet, that the hedgehogs are coming to you for food, so I would suggest getting a small bag of cat or kitten biscuits to start with, or a small ‘sample’ sized bag of hedgehog food, so there isn’t too much waste. The hogs might be more attracted to it too. Even more than food, water is very important, and they would welcome a constant source of water in your garden – absolutely essential if you are feeding dry food.
I am guessing you don’t have a night cam, so wonder whether you might find it interesting to try out a footprint tunnel. It would prove whether the hogs are really coming into your garden, and you might see what else has been there as well. The following are some links about them. As you are obviously handy at making things, you may even be able to make your own.