Considered discussion to follow (possibly).
This phrase seems to be the most important one: "The material featured on this site is subject to Crown copyright protection unless otherwise indicated. The Crown copyright protected material (other than the Royal Arms and departmental or agency logos) may be reproduced free of charge in any format or medium provided it is reproduced accurately and not used in a misleading context. Where any of the Crown copyright items on this site are being republished or copied to others, the source of the material must be identified and the copyright status acknowledged."
- Government Crown copyright FAQ
- w:Crown copyright
- Click-use license
- Application form
- MediaWiki:CrownCopyright, MediaWiki:CrownCopyrightText
- Can the w:Freedom_of_Information_Act help us, or do we need to allow non-GFDL sometimes (perhaps for a limited set of exceptions such as this one)?
- Could this be considered a flaw in the GFDL? After all, the objective of ensuring accuracy (what the user of the work must ensure in his own writing and what those who further license the work from him are also bound to do) is not against the spirit of the license, is it?
Previous enquiries and discussion 
- Pronouncement by Jimbo :-(
- The Epopt's letter to w:Her Majesty's Stationary Office
- Waiver of copyright?
Relevant articles and projects 
- Is this list copyrightable? I don't think it is under US law, but under UK? Might special permission be requested? Do we need to allow modifications that are not accurate? Is this a flaw in the GFDL?