/**
 * Implementation of hook_views_pre_render().
 * Check to reduce the number returned items to 2 from 3 if an advert is present in the view attachment. 
*/
function modulename_views_pre_render(&$view) {
  //bit nasty?
  global $alter_num_results;
  if (($view->name == 'News' && $view->current_display == 'block_1') || ($view->name == 'News' && $view->current_display == 'attachment_1')) {
	//If the attachment has a result nid then it has an advert to display so mark alter_num_results as true
	if($view->current_display == 'attachment_1' && $view->result[0]->nid){
		$alter_num_results = 'TRUE';
	}
	//If the marker is true then unset the 3rd item
	if($view->current_display == 'block_1' && $alter_num_results == 'TRUE'){
		unset($view->result[2]);
	}
  }
}