Hi Slugfest
Sometimes hedgehogs take a while to ‘accept’ a new house, and won’t use them until they become part of the landscape, so I think if you placed them in accordance with the guidance from Hedgehog Street
https://www.hedgehogstreet.org/help-hedgehogs/hedgehog-homes/
I would be inclined to leave them and they might eventually be used.
If you put lots of potential nest material nearby, it might give him the idea, so leaves, grasses, hay, etc. You might like to put a very small amount of material in the box to start it off, but many hedgehogs prefer to make their own nests.
Good luck.
