use strict;
use warnings;
use Data::Dumper;

my @clients;  # make this an array, not a hash;
my @fields = qw/surname firstname town/;

while (<DATA>) {
    next if ( /^Surname/ or /^-/ );
    my @values = unpack 'A13A16A20', $_;
    my %entry = map { $fields[$_] => $values[$_] } ( 0..$#fields );
    push @clients, \%entry;
}
print Dumper(\@clients);

__DATA__
Surname L20, First Name L20, Town L20 
-------------------------------------------------- 
Chaplin      Charlie         Basel 
Estevez      Emilio Santa    Manica 
Sarte        Jean Paul       Montmarte 
Rikard       Frank           Amsterdam 
Rodin        Paul            Montmarte