Why didn't I think of this before?

Just reread John Buchan's "The Thirty Nine Steps". I don't know how I missed the all embracing plot hole before. The whole thing turns on a fiendish German plot to obtain the British Admiralty's mobilization dispositions. And if the Germans get them they will have to be changed which is problematic because they are rather constrained by geography. Just so. The possible dispositions of the Royal Navy in the event of war between Britain allied with France against Germany are extremely constrained by geography. So constrained in fact that any half way decent naval staff officer would be expected to guess them with some precision. Which makes stealing them rather less than fiendish...