You can also purchase recording and booklets of the South Yorkshire and Derbyshire carols from

http://www.villagecarols.org.uk/CAROLS/vcpublications.htm

I have put the shhet music and MIDI for a number of them, like 'Back Lane' and 'Diadem', on the folkinfo site. See http://www.folkinfo.org/songs/keywordsearch.php?keyword=134