The problem turned out to be that, although not one single piece of information in either article was classified, GCHQ [Government Communications Headquarters] feared that the way that all the individual Unclassified details were put together made the articles as a whole Top Secret.
This is not as crazy as it sounds. W.E. Butler, founder of the esoteric school Servants of the Light, said something very similar about the fact that a lot of the ritual used in magic is now in the public domain:
The question arises, why should the various magical orders have sworn their initiates to secrecy concerning these things which are of common knowledge? The answer is, that in those orders and fraternities which were genuine the information given in these various sources was combined in a particular pattern, and it was this pattern which was the real object of secrecy.
But really, GCHQ had simply panicked.
– A Brief History of Secret Societies: An Unbiased History of Our Desire for Secret Knowledge (1997), pp. 260-1