"Becoming Holmes" by Shane Peacock

I'm a bit irked with this book, I'm afraid.  I started reading this series three years ago because the title of this, the final book, sounded so enticing.  I worked my way through them slowly, because there were only six books in the series, and I didn't want them to get to this one too quickly.  I liked the series better and better as it progressed, and so I'm afraid I set myself up for a bit of a let-down, as I did have pretty high expectations for Becoming Holmes.  

It's...