The writing is excellent.
During the fire I truly felt the terror and angst.
I truly enjoyed the book very much, but every once in awhile your Holmes and Watson got in the way.
As an avid Sherlock Holmes fan I feel your Holmes was a bit on the slow side and while Watson was never a gazelle, I don’t believe he has tripped so many times in one book.
I think you would be better off creating your own characters.
Your writing is good enough to stand on it’s own. Personally, I believe you limit yourself when you use someone else’s characters.