Hello ozboomer,

tangent beat me to it with %I. But you should also check for errors; e.g.:

my $dmy_fmt = DateTime::Format::Strptime->new
   (
       pattern   => '%d/%m/%Y %I:%M:%S %p',
       time_zone => 'Australia/Victoria',
       on_error  => 'croak',    # <-- ADD THIS
   );
[download]

With %H instead of %I, this reports:

13:08 >perl 1989_SoPW.pl
$dtnow: !2019-03-25T20:10:32!
 $lodt: !2019-03-18T10:12:53!
Parsed an input with 24-hour and AM/PM values that do not match - "3" 
+versus "pm" at 1989_SoPW.pl line 48.

13:10 >
[download]

— somewhat cryptic, but an indication that DateTime::Format::Strptime is expecting 24-hour and not 12-hour time here.

Hope that helps,