UPDATE: This guy explains what the joke is, and that makes it more likely that it was an anonymous political joke/pastiche. (Although a commenter points out that Doyle didn’t actually become a candidate until three years later, he was obviously known to be dabbling his toes into it.) Two similar “interview” pastiches were also published in The Book o’ the Brig (Sir Walter Scott and Mungo Park) and they came immediately before the “Sherlock Holmes” one; so it seems that the guy promoting the story’s discovery was concealing them to make a bigger splash with the third.
It’s still a pretty cute pastiche, but the way it’s been presented was pure clickbait and switch.
So yeah, you can ignore all this stuff below!
First off, if this is authentic, then the Estate of Arthur Conan Doyle has some ‘splaining to do. Pretty bad recordkeeping, guys.
Second, here you can read the long-lost story from the charity fundraiser, The Book o’ the Brig.
Third — since it was published anonymously, is it really Doyle? That’s a reasonable question. I think it sounds right, and Doyle did publish some other bits and pieces for charity that had a similar tone. OTOH, it would have been unusual not to publish it under Doyle’s name, not to mention putting it in the place of honor at the beginning of the book.
OTOH, if it’s a pastiche, it seems unusual to have published it anonymously; usually these things went under joke names). Possibly it might have been by a local politician or journalist, one supposes, but why the anonymity?
Fourth — the burning question. Is it Canon?
If it is indeed authentic, the framing device would seem to indicate that Watson’s Agent, Doyle, got a certain level of cooperation from both Holmes and Watson, and got Watson to contribute something for the bridgebuilding fun. Certainly the feel of the story indicates that Watson wrote it up. But apparently Watson was using his pawky sense of humor at full force, as he rips on both his own (obviously unsuccessful) essay into politics, and Holmes’ stalkerish chains of observation and deduction.
So I would say that it might chronicle actual Canon events, but in a humorous and unrealistic way.
Fourth — if this is authentic, obviously Sherlockians doing research into Watson have fallen down on the job! How could such a chapter in his history have been totally forgotten!
Fifth — And really, I’m pretty surprised that this book was missed for so long. People collect early pastiches as well as the more modern ones. I’ve never seen it on lists of early pastiches, though. Sherlockian studies and collectors are shockingly completist, to the point where you start to think they’re as all-seeing as the Oculus Dei on the dollar bill. But no! Bibliophiles are still fallible, and hidden treasures are still out there to be found.