] I've only just discovered this -- probably everyone else has known about it for years.

Yes we have ;>)
I'm surprised that you didn't know of it.
It's bound to come up if you look for Jane Austen on the web.
It's a very pleasant book to read and follow her in the footsteps of Jane, and because(since the year was 1900)she was able to visit a number of houses that doesn't exsist any more. Such as the Digweed's House, the Assembly Room at Basingstoke and Kempshot House where Jane went to balls.
And even a house in Lyme where she stayed. Although that seems to be a bit uncertain.
I downloaded the book and printed it. But I can't recommend that.
It was too much work.
It seems to be difficult to find the book now at a reasonble price.
But I like to recommend another biography wich you can also find as an e-book. It's 'Jane Austen and her Times' by G.E.Mitton (1905).
She tells everything that's of importance about the subject for an Austen fan. With chapters such as: The position of the clergy; Home life at Steventon; Society and lovemaking;The novels; The navy; Bath; Dress and fashion; and more in 19 short chapters. A book that I'm sure will tempt to further reading.
If you wish to buy the book,you should be able to for as little as $10.

Leif G-n