protected function getVersionedLogo()
{
$path = Yii::app()->basePath . '/assets/img/_print/';
$url = Yii::app()->assetManager->publish($path);
$logo['headerLogo'] = $url . '/letterhead_Moorfields_NHS.jpg';
$logo['secondaryLogo'] = $url . '/letterhead_seal.jpg';
return $logo;
}