We have concrete plinth under the fences around almost the whole garden. We know hedgehogs come in and out via the hole under the gate. This one came into shot from the right of the camera so it either got in through a gap we don’t know about or it’s living “within these walls”.
My Dorset Home 
Tried to like photos but it doesn’t seem to recognise me
Oh. Don’t know the answer. Maybe next time it will all drop into place!