The attacks here on the Guardian are unfair. The Heaney error was very rapidly corrected by the paper (on the same day) and a prominent note was added at the bottom of the article to that effect. It's my experience that the Guardian is generally at least as accurate in its reporting as any other paper and, unlike most other UK papers, it does not commit the journalistic crime of vexatiously mixing reporting with comment. Of course, nothing is perfect.