I have a copy of The Linguistic Atlas of England (Croom Helm 1978) but I don't think it covers terms of this sort (it does have a comprehensive "Earth Closet" section, though). NATCECT's own website, incidentally, is at

http://www.shef.ac.uk/english/natcect/index.html

I was fortunate enough to have had John Widdowson (the founder of the Centre) as my departmental tutor when I was an undergraduate, and to have taken his Folklore course the first year it was accredited as part of the degree. My rather scruffy work on Toilet Graffiti is still held in the archive there, though the last I heard, you had to ask for it specially, as it wasn't the kind of thing that they wanted inadvertently to inflict on casual visitors.