Ok, I've turned on error reporting as you requested. I'm not sure exactly what I'm looking for, but it appears to me the only errors being reported are:
JROOT/administrator/language/en-GB/en-GB.com_rokgallery.ini : error(s) in line(s) 9, 17, 53, 158, 159, 371
JROOT/administrator/components/com_rokgallery/language/en-GB/en-GB.com_rokgallery.ini : error(s) in line(s) 9, 17, 53, 158, 159, 371
There's a RokGallery button on the bottom of all my WYSIWYG editors.
What I do notice is the database table #_hikashop_product_related is being changed for more than 1 product when I only make a change to 1 product.