NATS has been the 'face' to the media of the UK's decision to close its airspace in the face of this unprecedented event. I would sugest that this has been been politically expedient for the higher echelons of govenment and, perhaps, the airlines (initially) to have NATS as the 'fall' guy as and when blame begins to be bandied around at a later date as will inevitable happen.
judge11, quite agree with your comments here. I touched on this aspect early on in this thread.
Also, many operators have a/c and crews stranded away from base. As part of the evaluation why not permits selected a/c to return to base as a ferry? I strongly suspect that all these flights would operate without incident. This would ease the pain for when operations start, return a/c to engineering bases and mitigate costs of parking etc and keeping crews in hotac etc
Of course we should take into account what the boffins are telling us but as pilots we are used to evaluating relative risk. If you want 100% safety then keep the aeroplanes in the hangar! Even the BA flight landed safely in 1982, albeit with substantial damage.