I started writing this to play after Christmas Mass in the late 1980's, however it didn't get finished until 1991, and had its debut performance at St Michael's Retford Carol Service in that year.
For those interested in production techniques, this performance was created with the Jeux organ soundfont, with the addition of a nice Acoustic Mirror reverb in SoundForge. It sounds pretty good although there are some MIDI timing problems which I suspect are caused by the density of MIDI data - I ended up using 14 out of the available 16 channels to get the layering I required, which was probably a bit too much for the SBLive 5.1 it was performed on.