I can't quite figure out what to say about this book. It is an incredibly weird little tale, and, to be honest, it isn't really much of a mystery.
Here is the note about the author from Goodreads:
Frank Collins Richardson, barrister, and novelist, was educated at Marlborough and Christ Church, Oxford, afterwards entering the Inner Temple and being called to the Bar. But there, as he admitted, he was a failure, and he took in consequence to writing, his "King's Counsel," a novel, appearing in 1902. It was followed by some dozen others. His peculiar topic of humour was the subject of whiskers, which he discovered by accident, and perhaps worked for rather more than it was worth. But his treatment of it was hailed at the time as an amusing innovation, and by pen and pencil, and by judging at seaside male "beauty-shows," it cannot be said that he was wholly unsuccessful in his peculiar hobby. (from obituary in "The Times", August 2, 1917)
I added the bold.
Which brings me to one of the weird elements, which is, of course whisker humor. Who would've thought, really, that whisker humor was a thing. I would certainly agree that he worked it for rather more than it was worth - I was tired of it about ten seconds after it was introduced. Obviously, times have changed, although in this era of peak hipster beard (estimated to have occurred in 2014), I suppose that there could be some mileage to be gathered.
There were elements of this book that were interesting, and could make for a fine study of gender crossing, queer theory, and whatever else one might be looking for. I was, however, looking for a mystery and with that, I cannot recommend this book.