After playing and singing "Down in Yon Forest" many times, I did change the key before recording my Christmas tracks about a year ago, and my singing of it does need more work...I may drop it shortly and re-do it one day with "organ" rather than "piano" accompaniment.
But, as for the others, including "O Come all Ye Faithful", a year on, I think the quality is about the same.

Jazz is an aspect of American culture, SURREYsinger - I'll keep working at playing and singing just the unadorned unadulterated tunes of English chants, carols, hymns and folk-songs, thanks.