PeterC66 on "A default script seems to load instead of mine"

I have a working site and have just upgraded it. One tiny thing is now working oddly and I cannot work out why. You can see the problem at http://www.hcnhistory.org.uk/public-houses/.

The images in each row of the table are little galleries using the plug-in New Simple Gallery (NSG Version 6.3). If you mouse over one of them you will see 3 symbols at the bottom, and these should be back/play/next icons. The functions work, but the correct images do not show.

This is a known problem with NSG, and I have solved it by changing the URL addresses in the new-simple-gallery.js script (line 21). This works fine on my WAMP, and worked on my previous version of the live site.

What seems to be happening now on the live site is that a default version of new-simple-gallery.js is being picked up from somewhere, and my version is not being used.

In the php file it uses the following function to load the script:

function nsg_add_javascript_files()
{
	if (!is_admin())
	{
		wp_enqueue_script('jquery');
		wp_enqueue_script('new-simple-gallery', get_option('siteurl').'/wp-content/plugins/new-simple-gallery/new-simple-gallery.js');
	}
}

if (is_admin())
{
	add_action('admin_menu', 'nsg_add_to_menu');
}

When I use Chrome's inspect element I can see that the left/play/right icons are all there in the resources for the page twice - once correctly and once incorrectly.

Again looking at inspect element I see the incorrect script seems to come from the correct location in my site. Even if I delete my script, the site still works, as it is still picking up the default script.

I do not think that I have changed anything in this area. Where do I start to look next? I have already cleared the cached files. There is not much activity on the plugin's support site.

I realise it is probably a simple problem. Thanks for any help you can offer.