I also live in Notts and to be honest I've not even been near my pond since the snow stared but I suspect like yours it is frozen, however I doubt if it is solid, as Helen there is usually a bit were the fish can hibernate. I never bother trying to stop the pond freezing and in fifteen years I've never lost any more fish in winter then I would expect at any other time, mind you it is about 4ft deep and I'd be surprised if it froze to that depth in this part of the world