Father Christmas - ah at last you are talking my language Michael. A good pagan symbol (solistice, ending of winter etc). And the flying reindeers, even better, hermits in Central Europe would high on mushrooms would imagine that they saw the reindeers flying (think there is also a story that they would drink reindeer wee as the reindeers themselves liked the mushrooms and the hallucinogen was still active).

Coming down the chimney? Again back to our friends in central Europe, where during winter in the snow the chimney was a hole in the centre of the roof that also acted as a door.