You are a pretty imaginative interpreter yourself. The "Shores of France" are not mentioned anywhere. Yet you have decided that the chronologically mis-positioned description of a message "signalled accordingly" must be it, and ignore that it is described as happening after the Luftwaffe left their bases on the 27th. Very close to 11:37B/27.
Here's the digest. I am verbose because it is so much fun shooting holes in your specious speculations.
However it already too late, as it crosses with the information Winston is desperate to hear to relieve the unrelentingly bad news, and gets in the House a little while later. It is slightly more stupid as a result, but nowhere as bad as the exaggeration Tovey thought up nine years later, and which neither Kennedy nor Roskill believed enough to print.So Winston was aware that Tovey's guns had failed to sink Bismarck, before he started speaking on the morning of the 27th, and undoubtedly pestered Pound with the "tow home" twaddle he had thought up the previous night, resulting in the 11:37B actually being sent. Pressured by the PM moments before he was to address the House of Commons with unrelentingly bad news from Crete, Pound is instructed to send a "fairly stupid" signal to Tovey.
This is a far more sensible interpretation than Pound sending a message of "criminal stupidity" and Tovey forgetting to mention it in a letters to Pound a few days later.
All the best