I'll add one: how about whoever (probably Grey and Haldane, with Asquith's tacit approval) let Henry Wilson be in charge of the British staff talks with the French in the run-up to WWI. (Without informing the rest of the cabinet.) Wilson got infected with the Bergsonian "spirit" of the French general staff and bought all their crap about the offensive and elan, , etc. Then he managed to convince the British general staff (although not Kitchener) that the Germans weren't really building up behind Liege, and even if they were strong on their right wing, it wouldn't matter because the French would just cut them all off from their base.
I think a key events you are referring to is the renowned meeting of the Committee of Imperial Defence in 1911 when the Cabinet was treated to presentations by two Wilsons, one from the Army and another from the Navy.
Admiral Wilson, gruff and ineloquent as he was, gave a presentation that vaguely laid out plans for close naval blockade together. 'Shambling and ill-thought out' as Sir Hew Strachan put it. In contrast, General Wilson, as consummate a politician as he was a soldier, spoke convincingly about the need for the BEF to be sent to France in the event of war.
The Navy's supporters were apparently not there and the influence of Churchill and Lloyd George was decisive. That made the deployment of the BEF to the continent an orthodoxy.
Not that it had to be adhered to doggedly. The decision to send the BEF to operate on the French flank was really made the day after war was declared in August 1914 by an ad hoc committee consisting of much of the Cabinet and a panoply of army officers including French, Haig, Murray-Wolfe, Kitchener and even, if memory serves me right, Lord Roberts. Field Marshal French wanted to place the BEF on the Scheldt to attack the German flank. Churchill squashed him - figuratively. General Wilson didn't actually speak, but he got his way.
So the decision was ultimately arrived at in an amateurish, muddling sort of way. Very Asquithian, really.