You'll have a wonderful time there; hope the weather cooperates. London is nice, but everyone goes to london and gets similar shots. The day trips is where you'll really find the gems. Hope you don't mind if I post a few small ones from my recent trip:
Bath is about an hour to the west:
Then to the south about an hour is the resort city of Brighton (however probably not a lot of people go there during the winter:
Stonehenge you could almost pass up completely, but your friends back home will complain if you don't at least go just to see these stones:
I found them pretty uninspiring, however.
And if you have the chance to head to the highlands of Scotland, you won't be dissappointed:
Eiliean Donan Castle
I think the weather might be your largest obstacle. But again, it comes down to what you want to shoot, and how adventerous you are. Also, how much money you want to spend on gas, since it's about $90 to fill up over there.
Good luck and have fun!
--
John Mueller
Photographer / Engineer / Comedian / Dad
http://www.flickr.com/photos/johnmueller/