Product Page Intro Text Joomla 3

-- HikaShop version -- : 2.6.2

Hi
A long time ago, I was given the following code which enabled me to show the readmore text of the product description which I put in the Top Right Part or under the Product Title. It works great in my Joomla 2.5 but doesn't work in Joomla 3 so assuming the php code is wrong - I am not a programmer so have no idea.

<div id="hikashop_product_intro_text" class="hikashop_product_intro_text">
<?php
echo preg_replace('#<hr *id="system-readmore" */>.*#is','',$this->row->product_description);
?>
</div>

Also,
Is it possible to just show the product details without the readmore (intro) text so that if I use the above, its not appearing twice on the same page.

I found an old thread and some code and managed to get it working with this:

<?php
if(!empty($this->element->product_description)){
$resume = preg_replace('#<hr *id="system-readmore" */>.*#is','',$this->element->product_description);
echo JHTML::_('content.prepare',$resume);
}

Not a programmer but assuming it could probably be shortened.