It looks very interesting. I like these sort of books, where they take real people and fictionalise contemporary events, then add some fantastical elements to provide new twists on old tales. The "thin wobbly plot" is a little worrying, but I've read plenty of those that gave me lots of entertainment, so I'm not too bothered.
In a similar vein, I read a novelisation of how Wells might have come to write War Of The Worlds, which involved several real and imaginary Victorian characters, aliens both dastardly and friendly and ... well I won't spoil the plot.
Sadly, being an old fool, I've forgotten the name of both book and Author
It was pretty good though and showed plenty of imagination and deft touches.
The List of Seven, by Mark Frost is another one worth reading and does a similar thing with Arthur Conan Doyle, showing where he might have got the inspiration for Holmes and Watson.