One year is not long to leave a potential hog house in place. Some hogs will use them immediately, but others won’t until they become part of the scenery, i.e. for a couple of years. So it is best to decide on a good place for a hog house (of any description) and then leave it there.
It is never a good idea to disturb hog houses, especially if there appears to have been some kind of bedding taken in. A mother hedgehog will sometimes desert or kill her young if they are very tiny, if she is disturbed. Hog houses should only be disturbed or cleaned out if you are absolutely certain that a hog isn’t using it. The stick test is a good idea, but if the mother is in there with very small young, she may not come out for a while. It’s difficult to know whether there is something dead in the nest with the flies outside. But I would be inclined to leave it, again, unless you are absolutely certain that it is the box which is attracting the flies – that there hasn’t been any food nearby which could have attracted them, etc. – and that the box is not being used.
Really it’s best not to intervene with hedgehogs at all, unless they are obviously sick or injured. i.e. out in the open during the day, sunbathing, etc. which are not normal behaviour. They have been managing for millions of years without our help. So providing them with boxes, is fine, but to them that is just a structure which they can build their nests within – similar to some bushes planted close together, as in hedges, etc., but then let them get on with how they choose to use them.
If there were hoglets in a nest, depending on their size/age the mother may take a break from the hoglets, and rest somewhere else. That is one of the exceptions to the rule that hogs should not be out during the day time. Nursing Mothers will sometimes take a rest away from the hoglets during the day. (the Mother has sole care of the hoglets – the Father has nothing to do with raising of hoglets and is likely not to even know his offspring, should they ever happen to meet)
You might find the following interesting:
Although a degree of common sense is required. Sometimes a box needs cleaning out at other times, but as mentioned previously, do not disturb unless you are absolutely certain that the box isn’t being used.
Good luck with the hogs. Hopefully there are some hoglets around somewhere and you will soon see them.