Got it working by installing PHPtidy and validating the HTML, it seemed that & signs were causing some issues
$doc = new DOMDocument();
$data_text = str_replace(' ', ' ', $data_text);
$data_text = str_replace('&', '&', $data_text);
$doc->loadHTML($data_text);
$html = new WordFragment($docx, 'document');
$html->embedHTML($doc->saveHTML());