Who knows what we're allowed to photograph??
"did the photographer have permission to photograph what is possibly a prescribed place under the official secrets act?"
Where and what is a "proscribed place" (or more accurately "prohibited") is almost impossible for the "man on the Clapham omnibus" to now work out if even the Ministry of Justice don't have a clue:
http://p10.hostingprod.com/@spyblog.org.uk/blog/foia/2008/09/current-prohibited-places-under-the-official-secrets-act-1911.html