Searching for what is not there using REGEX in only a single step

[Michael ODonnell]

It's possible you could approach the problem more
simply, maybe like this:

   starting from every instance of </fh> start
   gathering all text except anything that looks like
   a tag (ie.  discard all tags) up until the point
   where you find an instance of </location_addr1>.
   You're then situated where you have the desired
   text (sans tags) and you know exactly where you
   are, so you should be able to utter (that part of)
   your record with the desired format.  In other
   words, instead of rewriting just the damaged
   records, rewrite ALL the records.

...just a thought, based only upon the info supplied,
FWIW, YMMV, etc...