The tune is also to be found on some of the links from a recent thread on the South Yorkshire Carols Blicky. A site which has both words and a MIDI file can be found here Blicky. If you use Internet Exploder, Hail plays in the background, but on Netscrape it doesn't.
Hail Smilimg Morn is a great favourite at the South Yorks events, although the words they sing around Sheffield do differ slightly from the printed version.

Quacking along!
Geoff the Duck,
p.s. I am waiting for the feathered version - Quail Smiling Morn......