I'm no expert, but they do suffer with fleas, etc. Those on my unedited video, are often seen scratching. Maybe the slowness is due to becoming drowsy and making ready to hibernate. Don't know where in UK you reside, but think that with the cooler nights now, hibernation is now on the cards.
Down here in the south, still eating well, and will have to buy yet another bag of dry cat food, and no the cat can't get to it, being tucked well under my shed. Must say was fun firstcouple of nights, watching him/her on camcorder video, trying to crawl under to reach it. Head and a shoulder only, so gave up, and now never bothers to stop.