Thankyou everyone for their ideas and comments, I how have a prototype that works for me(pending more tests). The program 'remembers' and can 'recollect' two particular values( tell FH , $st_ino ). This behaviour is coded by hand for now, but if it gets too cumbersome then I think Data::Dumper (which is now my latest fav module) will help me out.

blm - you were right to warn me about those rotating logs, and I am experimenting with some 'awareness' in the program for coping with this. Though I'll be reading some more before I settle on this, it appears that keeping track of the inode number as given by file stat, gives an indication as to the 'sameness' of a given file. That is, after a logrotate the file /usr/local/squid/logs/access.log possessed a different inode number. I am using this approach only because I can determine no other way (TMTOWTDI) to glean this info.

#!/usr/bin/perl -w
package HotSaNIC::squid;
use strict;
use File::stat;
use Data::Dumper;
use Carp;

sub new {
  my $self = shift;
  my $settings = shift;
  # Open the settings, slurp into hash.
  my %settings;
  open ( FILE , $settings ) || croak "Cant open settings, $settings $!
+";
  while (<FILE>) {
    # throwout comments/blanks
    next if ($_ =~ /^#/);
    next if ($_ =~/^\s+$/);
    chomp;
    my ($var, $val);
    ($var , $val ) = split '=' , $_;
    $settings{$var}=$val;
  }
  $settings{TIME}=time;
  return bless {%settings}, $self;
}

# Open a file to read persistant data
# recollect returns the offset from BOF for seek (where)
#                   and the inode number of the log when we saw it las
+t.
sub recollect {
  my $self = shift;
  my ($where , $node, $data);
  open ( F , '<.p' ) || return (0,0);
  $data = scalar <F>;
  close F;
  $data =~ /(\d+):(\d+)/;
  $where = $1;$node = $2;
  print "Recollected $where , $node\n";
  return ($where, $node);
}

# Write info back to persistant file.
sub remember {
  my $self = shift;
  my ($where , $node) = @_;
  open ( F , '>.p' ) || croak "Cant open persisting file";
  print F "$where:$node";
  close F;
}


sub go {
  my $self = shift;
  my ( $where , $node , $logstat, $pos);
  my ( $time , $duration , $result , $bytes);
  
  ($where , $node ) = $self->recollect;
  $logstat = stat ($self->{LOG});

  # Compare atime of log agains the persistant info.
  if ( $node != $logstat->ino ) {
    # Oops, the log has been rotated since we last ran
    print "Oh crap , someone spun the log beneath us!\n";
    $self->remember(0, $logstat->ino );
    $where = 0;
  }
  # Fiddle through the log
  open ( LOG , $self->{LOG} ) || croak "Cannot open log ,$!";
  seek LOG , $where ,0;
  $self->{POS} = tell LOG;
  $self->{DURATIONMIN}=999999; # A very big bogus number
  $self->{DURATIONMAX}=0;
  $self->{BYTESHIT}=0;
  $self->{BYTESMISS}=0;
  $self->{GROSSREQUESTS}=0;


  while ( <LOG> ) {
    
    if ($self->inInterval($_)) {
     # DO Something with this VALUABLE information
      # Moreover ,  set $self{POS} to mark position in file.
      #print "$_";
      $self->{POS}= tell LOG;
      ($time , $duration , $result , $bytes , undef) = $self->breakLin
+e($_);
      # Tally up some figures
      if ($result =~ /HIT/) { $self->{BYTESHIT} += $bytes };
      if ($result =~ /MISS/) { $self->{BYTESMISS} += $bytes };

      if ($duration > $self->{DURATIONMAX}) { $self->{DURATIONMAX} = $
+duration };
      $self->{GROSSREQUESTS}++;

      if ($duration < $self->{DURATIONMIN}) { $self->{DURATIONMIN} = $
+duration };

    }
    
  }
  if ($self->{DURATIONMIN} == 999999) { $self->{DURATIONMIN}='U'};
  if ($self->{DURATIONMAX} == 0) { $self->{DURATIONMAX}='U' };
  
  $self->remember( $self->{POS} , $logstat->ino );
  print Dumper $self;

}


sub breakLine {
 # Splitter for squid access logs
 my $self = shift;
 my $line = shift;
 my @data = split " ", $line;
 splice @data , 2 ,1;
 return @data;
}

sub inInterval {
  # determine if the passed line is in our interval range.
  my $self = shift;
  my $line = shift;
  $line =~ /^(\d+\.\d+)\s+/;
  my $time = $1;
  ($time <  $self->{TIME} ) and
        ($time > ($self->{TIME}-60) ) and
                return $line;
  return undef
}


package main;
use File::stat;
my $zz= HotSaNIC::squid->new('settings');
$zz->go;
[download]

Ok Monks, go ballistic - I'm please I got this far but it's still pretty messy. Thankyou all again for your help.