I'm using this formula to return a 'current' or 'expired' value depending on
the date in column B (expiry after one year). *Because I want to autofill
rows that don't yet have data, I require some extra criteria so that no value
is returned if B is still blank. *Comprehend??

=IF((TODAY()-B4365), "EXPIRED", "CURRENT")

Maybe something like this would help:
=IF(B4="","",IF((TODAY()-B4365), "EXPIRED", "CURRENT"))