Fix display of "External reference" and "Import source" when viewed by an official. Also, a fix for problem that affected Genshi too - duplicate display of "External reference" for an ONSHUB dataset viewed by an official.
Fix errors when displaying UKLP dataset e.g. /dataset/lidar-digital-surface-model
Merge branch 'taxonomy-integration' of github.com:datagovuk/ckanext-dgu into taxonomy-integration