The season of Advent, for most children, means anticipation, gleeful waiting, the counting down of days. But after a certain age the build-up to Christmas changes its nature, becomes more like anxious preparation. It can, though, be thought of as a time of reflection. Radio 3’s Christmas Around Europe has for years nourished that feeling by taking us on a leisurely, day-long musical tour around the continent, usually on the last Sunday before Christmas.