I think most readers and lovers of Austen will know before picking up these pastiches and "extensions" whether or not it is their "scene" and therefore should not be hypercritical simply because a writer has attempted one. I have not read many of them and so tried to approach this one from a neutral POV. Capt Wentworth and Col Brandon are two of my favourite Austen male characters so I was intrigued to see what the author would do with them.
The story is a good "fit" with Persuasion and I think that overall the author has done a good job of creating a workable synergy. She fills in some gaps, shows how the initial courtship may have progressed and imagines Frederick's feelings about it and the resulting rejection. I liked his brother Edward who gets quite a central role in this book and is that sort of robust, jolly, down to earth, sensible clergyman so much missed today in the C of E. I'd have liked to learnt more about his story and his wife.
If there is a downside to the story, for me it is that I am not now so sure if I still love Capt Wentworth. In some respects, he is a little hard on Anne (owing, I suppose, to his own youth initially) but once he meets Anne again, I thought that he does act pretty realistically for a young and ambitious man. He is pretty class conscious himself making a good match for Sir Walter's snobbery. And yet, he has friends and family who are strictly middle class. Somehow, the author has given him not one but two clay feet and in doing so, has rubbed off a little of his romantic glow.
I agree with the reviewer here who said it was as well that the author did not attempt to write about his naval career - that would have been very much against the grain of Austen's stories because she never directly alludes to current events in her life.
All in all I think this was a pretty good effort and I look forward to reading Col Brandon's story which I think ought to be quite interesting.