I saw earlier tonight that we had a hedgehog visitor in the feeding station, and I also saw him a little later at the water bowl. I just assumed it was the same hedgehog as on Monday night. At about 10pm, I looked out the back, and seeing that the coast was clear (or so I thought) I stepped outside to check the levels of food.
Then when I turned back to the house I saw this little fellow and my immediate reaction was that he or she was a small hedgehog and I'd better get it inside and weighed.
It turns out that s/he's about 470g so is nearly big enough to survive hibernation but not quite. It's certainly bigger than the two autumn juveniles that I found last month. I have the hedgehog safe in a pet carrier with bedding, food and water, and I shall phone Tiggywinkles in the morning, tell them how much s/he weighs and see if they think I should bring him/her in for overwintering.