I have sorted it myself by amending the code in Precious Lite Pro: custom-functions.php (inc/custom-functions.php)

Amending the lines in function precious_custom_testimonails() as follows:

$return_string .= ‘<div class=”testimonials-carousel-thumbnail”>’.(( has_post_thumbnail()) ? get_the_post_thumbnail( get_the_ID(), array(88,88) ) : ”).'</div>’;
$return_string .= ‘<div class=”testimonials-name”>’.get_the_title().'</div>’;

to

$return_string .= ‘<div class=”testimonials-carousel-thumbnail”>’.(( has_post_thumbnail()) ? get_the_post_thumbnail( get_the_ID(), array(88,88) ) : ”).'</div>’;
$return_string .= ‘<div class=”testimonials-name”>’.get_the_title().’</div>’;