Existing Org ID is being filled in but not details

This is a set up where a membership is onbehalf of an organisation.

If you put the membership id in the url (e.g. 32 below ) it retrieves the employer's contact ID & puts it in the host name field. However, the field should be populated with a Host Name not an ID.

http://sandbox.civicrm.org/civicrm/contribute/transact?reset=1&id=2&mid=32

There is code in
Contribute/main:: function buildOnBehalfOrganization( )
to pre-fill the related contact address fields but this isn't working. The JQUERY in the tpl file does work to do this & is would perhaps be easiest to pre-fill it using JQUERY - but maybe not the most correct approach?

if ( $this->_membershipContactID )

{ require_once 'CRM/Core/BAO/Location.php'; $entityBlock = array( 'contact_id' => $this->_membershipContactID ); CRM_Core_BAO_Location::getValues( $entityBlock, $this->_defaults ); }