Passing a node refernce id to a form via hook_form_alter()
ok, figured this out incase anyone is interested, may only work for my use case but perhaps it will help someone else.

function mymodule_form_alter(&amp;$form, &amp;$form_state, $form_id){
    if($form_id == "rating_node_form")
    {
        // dont require title
        $form['title']['required'] = FALSE;
        // validate
        $form['#validate'][] = 'mymodule_form_validate';
        // call after form is built
        $form['#after_build'][] = 'mymodule_after_build';
    }
}

function mymodule_after_build($form, &amp;$form_state) {
       //set the nid to the argument of the nide you are viewing
       $form['field_bar_name']['und']['nid']['#value'][0] = arg(1);
       //set the default value
       $form['field_bar_name']['und'][0]['nid']['#default_value'] = arg(1);
       //set form value
       $form['field_bar_name']['und'][0]['nid']['#value'] = arg(1);
       return $form;
}