Modifying output from Product Tag plugin

-- HikaShop version -- : 3.2.1
-- Joomla version -- : 3.8.2
-- PHP version -- : 7.1.5

I am using the product tag plugin to insert product details in content. It works fine but doesn't have the option to include the product SKU, where would I need to look to add this to the display?

While I'm at it I would ideally like to add the product category and a custom field from the category ( in this case an image additional to the product image ). I'm not asking for a complete solution just need to know where to look to modify this.

Many thanks,

Ian

I've tried adding the following to hikashopproductinsert_view.php:

<?php
		}

		if($this->code == 1) {
?>
			<!-- PRODUCT CODE -->
			<span class="hikashop_product_code"><?php
				echo $product->product_code;
			?></span>
			<!-- EO PRODUCT CODE -->

Thank you very much - it is working now.