I "bought" the book, and cracked it open with calibre editor.
Inside is a single HTML file, all CSS is applied directly via style attributes, chapters are separated by
Code:
<div style="page-break-after:always"></div>
and there are no ids to direct a link to.
The tox.ncx in calibre editor shows a bunch of links to "text/part0000.html" -- no fragment identifier. The ebook-viewer sees the same, I imagine.
On my Kindle, the Go To menu can see the chapters just fine (what id is it pointing at?

). Same with swiping up/down (the KT still allows you to flip though chapters like that).
darryl, you can submit a bug report at
http://calibre-ebook.com/bugs -- make sure to mark the bugreport as "private", since free books are still not permissible to redistribute. Submitting to a bug tracker (or private specialist) in private for development purposes is generally accepted as okay, allowing anyone to see the bug report and download the book (other than the developers in charge) is not.