Good God I didn't mean to set my self up as some sort of ladybird expert...
Some information I've learnt are that I was wrong, they're Asian and it's not just our ladybirds they effect, the could quite severely bu88er up the foodchain. They were bred in North America to combat plant pests apparently and they are much bigger hunters than our native ladybirds for greenfly. When they can't eat greenfly they'll eat other ladybirds, butterflies and other small bugs.
They don't like the cold much but I don't think turning your house in to a fridge will help. Scientists think that they swarm in groups in winter to nice warm places (I think ours do too) and that this could be down to their sense of smell. Potentially a box trap could be developed if this is the case but I don't really know what they are.
It's very important to paticipate in the harlequin survey (link above) as they are being monitored in this country and the scientists are asking for help in monitoring the wee beggers.
Our own ladybirds will come out of hibernation relatively soon and that's when they'll be effected big time but the bigger ladybirds.
It says that killing them now may not help and could mean you kill others by accident.
Lots of links for you here if you want to find out more like I did, (including a picture of their larvae so you know what to look for).
I will now be on my way as I actually have a phobia of all bugs and this is making my hair stand on end ever so slightly!
http://news.bbc.co.uk/1/hi/sci/tech/4348881.st m
http://www.rhs.org.uk/advice/profiles0108/harl equinladybird.asp