January 5 is the twelfth (and final) day of Christmas; the day before Epiphany.
Wassail is part of the observance, perhaps an incorporation of outside cultural elements turned into a time of blessing and shared celebration. (Though not too much)
So Cornish Wassail by Kate Rusby is a fitting place to finish this version of Christmas songs.
Thanks for following along through a down and up (and down) season.