well they normally do hibernate on mass in sheltered places . the last ones I sore were in an old ww2 pill box and there was about a 100 of them . I wish id taken a photo but hay ho . I think the very mild winter is throwing them out as they should be well hibernated bye now . the only difference I can see is that the green house lets in light which could be relevant if it warms up to quick . can you put some shade over it ?

Thanks, NP. There are number of clay pots in the greenhouse where it can shelter so might be OK. I will keep an eye on it. Very hard frost here today so goodness knows where it came from.

I have found this info. for you Gee:

Adult hibernation
However there are five UK butterflies that hibernate as adults: the Brimstone, Small Tortoiseshell, Comma, Peacock and Red Admiral. Two of these butterflies, the Small Tortoiseshell and Peacock, can sometimes be found hibernating in your house and may have been disturbed too early by your heating!

If you find a hibernating butterfly, you can gently remove it and put it somewhere that is unheated and sheltered from the elements, such a garden shed. Remember though that it will need to be a place from which the butterfly can escape in the spring, when it wakes up from its long sleep.

Thanks, Shirley. That is great - if it hasn't already disappeared somewhere in the greenhouse I think I might move it to the shed. It will be easier for it to escape from there I think, when it is ready.

Right, just had another wander down the garden and the butterfly is now settled into the shed, which I think will be more sheltered and won't have the glass/temperature problem of the greenhouse that NP made me aware of. Thanks, both of you :)

your more than welcome and not a strange question . nature doesn't care about boxing day .

I found one in one of the bedrooms again this afternoon. They're usually Peacock ones, but this was a Tortoiseshell.
I threw it out of the window and it flew away.

Wish I'd seen those in the pill box NP! Must have been quite a sight.

amazing stera and in a concrete bunker designed for war quite incredible .

I tried to find a blog from Bampy as I'm sure it was him had one overwintering in his conservatory, a couple of years back but it said account deleted......