Got to love Publishers that (try to) make the E-book look exactly like the print version by adding
blank Paragraphs between chapters.
Conversion will not fix this nonsense. You need to use the Editor and remove those.
No magic code, since how they actually do this varies.
Somethink like this will be just before the next chapter (anchor, if a single file)
Code:
<p class="xyz"> </p>
<p class="xyz"><br /> </p>