DV,
Prior to the accident the straight and level stall speed was the only stall speed immediately available on a vital data card to the pilot. This is what was meant by "documented". The stall speed in a manoeuvre, where G force is higher, will be higher. There was another discussion on pprune about this a few weeks ago. After the accident it was decided that the worst case manoeuvre stalling speed be put on the card, thus hopefully preventing another excursion outside the flight envelope.
Hope this helps.
By the way, folks, Mr Jimmy Jones, the man on tonights Panorama, is an ex flight engineer, who was involved with the flight testing of the Nimrod prior to its release to service. He will tell us (again) that the Nimrod was never designed for the Middle East. It is a fact that it was never tested in the Middle East, but that doesn't mean that the aircraft cannot operate there. It was tested for its intended use in the Cold War over the N Atlantic. This bloke obviously feels that he is some kind of Nimrod guru/forefather. The limited time and experience he gained on the Nimrod doesn't come anywhere near to the experience of some of today's Nimrod aircrew. I would take his words with a pinch of salt.