Someone at your link, in the comments (edit: just realised that it's you), claims the Crown Copyright means re-use is reliant on a revocable licence. Is that true? How can that be compatible with Creative Commons as they suggest here:

http://data.gov.uk/terms-conditions/

I'm a bit more worried by "you must ensure that you do not distort, mutilate, modify or take other derogatory action in relation to the information".

I don't even want them to restrict distortions, mutilations or derogatory actions (whatever the hell that might mean in relation to the location of public loos, or government spending figures). However, "ensure you do not ... modify ... the information" seems to defeat the whole purpose of the project.