Hi Ann
Hedgehogs do sleep outside, but normally in a fairly sheltered place, i.e. right in a flower border, bottom of hedges, etc. Those are the sort of places they would have to sleep if they didn’t have the option of a hog house.
The problem is more if they are out in the open and/or look as if they are sunbathing, behaving oddly, etc. Although it seems odd that he would find it too hot in a hog house at this time of year. I wasn’t sure from what you said whether he had been accustomed to sleeping in the box. Also not easy without knowing the terrain, etc.
But if you are worried about him you could contact your nearest carer – you can explain things to them in more detail. You can get contact details from BHPS on 01584 890801
