use strict;
use warnings;

my @email = (
    'someone@example.co.uk',
    'andrew.test@some.company.co.uk',
    'jo@abc.com',
);

foreach my $em(@email) {
	print "$em - ";

	$em =~ /^(\w[\w.])(.*)(\@\w\w)(.*)(\.\w+)$/;
	$em = $1 . '.' x length($2) . $3 . '.' x length($4) . $5;

	print "$em\n";
}