var RM_OLD, RM_NEW, PF_OLD, PF_NEW, PO_OLD, PO_NEW;

function CheckForRedirect() {

    if (parent.location.hostname.toLowerCase() === window.location.hostname.toLowerCase()) {
        
        var cleanURL = parent.location.hostname.toLowerCase();

        RM_OLD = 'postcodefinder.royalmail.com';
        RM_NEW = 'http://www2.royalmail.com/postcode-finder';
        PF_OLD = 'postcodefinder.parcelforce.com';
        PF_NEW = 'http://www2.parcelforce.com/postcode-finder';
        PO_OLD = 'postcodefinder.postoffice.co.uk';
        PO_NEW = 'http://www2.postoffice.co.uk/postcode-finder';

        if (cleanURL.indexOf(RM_OLD) > -1)
            parent.location = RM_NEW;

        if (cleanURL.indexOf(PF_OLD) > -1)
            parent.location = PF_NEW;

        if (cleanURL.indexOf(PO_OLD) > -1)
            parent.location = PO_NEW;

    }

}