#!/usr/bin/perl

use strict;

local $/="\n\n";
while (<DATA>) {
    print "$1\n" if /Customer\sID:\sYes\n(.*)/;
}

__DATA__
Customer ID: none
VT : 002/89

Customer ID: Yes
VT: 001/89

Customer ID: none
VT: 006/85

Customer ID: Yes
VT: 003/56