Well, talk about the land of confusion - turns out the rescue accidentally gave me the wrong hedgehog (they thought I had a larger 600gr male, not 450gr female - oops). Now before anyone jumps to any conclusions the rescue is fab, they really are - they look after countless wild animals and the set up is amazing and the week all this happened was the week they were prepping for their Christmas market and had lots of people helping out that normally don't work there that much.
So cut a long story short - when i checked with the owner of the rescue re the outside temps etc he realised what happened and with profuse apologies asked me to bring Mathilda back to them so she can be kept indoors in their rescue which I did on Sunday. She's now in very good hands with them, and come the spring I no doubt will be heading back there to collect a few of their hogs ready for spring release
So all turned out OK in the end
Thanks everyone for your help re electricity counting and all other aspects of outside temperatures and greenhouses etc... and if nothing else I think we've all learned a bit more about our prickly friends
x