Just picked up a copy of Cathedrals in Britain and Ireland by William Anderson and Clive Hicks (MacDonald & Jane's, 1978) in which we find but a single reference to a green man (a caption to a photogaph of one of the Chester misericords), with nothing in either the glossary or the index. Given that Anderson & Hicks's later Green Man (The Archeype of Our Oneness with the Earth) (HarperCollins 1990 & COMPASSbooks, 2002) and Hicks's own The Green Man - A Field Guide (COMPASSbooks 2000) are both 'key' works in the popular Paganisation of your common-or-garden EFH (Eccliastical Foliate Head), this strikes me as a particulary significant absence.