It’s difficult to know exactly what’s happening without a bit more detail. But there is some behaviour of circling reported in Pat Morris’ Hedgehogs’ book where a hog, on its own, will run round a circular track of 10 to 15 metres in diameter ‘without evident boredom or self-consciousness’. This can apparently go on for an hour or more.
When the book was written the reason for this was unknown, but there was a suggestion that it could possibly have been caused by exposure to chemicals or an ear infection. I’m not sure whether that’s what you’re describing, but if it is it’s a known behaviour. Someone else, might know some more up-to-date information about that.
I sometimes get a hog here who tears around into the feeding area, maybe grabs a quick bite to eat (but not always) and dashes off again the other side, but then may appear again a short while later, etc. I always think of that as ‘patrolling’ and that he (always a male) is maybe checking to see whether there are any females around. My garden doesn’t have an enormous area where a hog could run round and round, anyway.
The courtship circling would involve a female as well as a male. Where the male circles round the female as she huffs and turns round and round. But sometimes if she is against an obstacle, he will go round the obstacle as well. That can go on for hours, but your description doesn’t sound like that.
I wasn’t sure from your post, whether this only happened on one night, or whether the hog is repeatedly doing this on different nights. In any event, I would be inclined to contact your nearest hog carer/rehabilitator (you can get contact details from BHPS on 01584 890801) and see what they say, in case the hog is unwell/has an ear infection, etc.