By the way folks I have found a few "false positive" situations in using this plugin which I don't forsee being able to do anything about.
Here are a couple of examples I came across:
- A Wrox book which in one of the leading pages has a list of other Wrox books with their ISBNs, before the actual page containing the ISBN for this book. So it picks up the ISBN for some other Wrox book in that list rather than the one you have. The filth of publishers advertising in their own books I'm afraid.
- A book that had 2222222222 somewhere in the leading text. As it turns out by some coincidence that passes the valid ISBN check.
It is rare enough to not avoid using the plugin, but a reminder that this is just a tool trying to automate a human function of reading text and as such can sometimes get it wrong.