Hoddinott's Quodlibet on Welsh Nursery Tunes
Having just fetched our set of parts for the Quodlibet out of our library you might find the following information marginally useful.
The copyright for this piece was in 1983 by University College Cardiff Press. (UCCP 005) The address is probably way out of date but might be a good start for your search.
University College Cardiff Press, University College, P.O. Box 78, Cardiff CF1 1XL.