Well, if we want to be completely complete, The Unquiet Dead is a Christmas episode as well, but it aired in April and without Christmas brouhaha. The holiday just gets a mention at the beginning and end of the episode. Then again, Charles Dickens does feature.
Good heavens, I wish I’d done this ages ago. As the upload goes on, huge gaps are apparent where once there were beautiful screencaps. These things happen as time wears on and computers and various storage media break or go missing. Be assured, I’ll go after them again!