Not disputing that there is some 'voluntary' suppression of facts by the media but a quick search of BBC news shows 5 stories in the last 10 days.
http://www.bbc.co.uk/search/news/?q=GCHQ
(BTW, the 2nd result on that BBC news search is more like a job ad for GCHQ)
(Edited to remove my erroneous claim that D-notices aren't voluntary, turns out they are, though hardly any media orgs. go against them)
http://www.theguardian.com/world/2013/jun/17/defence-d-bbc-m...