Thank you for the advice and link Nic. I have ordered a second house in the hope the hog will move into it at least for a day or two, so I can clean the other house. I will keep the cameras out to keep an eye on the comings and goings, and try and get it done before the females come out and look to nest!
I had no idea male hedgehogs could be so aggressive towards each other until I caught the recent fights on camera. One hog even got flipped into a (shallow) water bowl! Thank goodness they have those spines to protect them!