How do I correct varying section breaks (epub to epub)

[library addict]

I have a book which is well formatted except for the scene/section breaks.

All of the scene breaks are marked, but some have no "extra spacing" above and some have varying amounts.

example 1:<div class="tx1">
example 2:<div> <br/></div><div> <br/></div><div> <br/></div><div class="tx1">
example 3:<div> <br/></div><div> <br/></div><div class="tx1">

Is there a way to correct this so they all have the same number of <br/> above using Search & Replace with regular expressions when converting in Calibre (ePub to ePub)?

Sorry if this has been addressed before. I have searched the forum, but had no luck finding the answer.