Adventure Tours - Theme Short Codes Plugin failing to load

Hi there, I have a bug that neither I nor our website developer can resolve and wondering if you can help.

When trying to create a post, the following error message appears:

Failed to load plugin url: https://iye.scot/wp-content/themes/adventure-tours/includes/shortcodes/tinymce/assets/ThemeShortcodesPlugin.js

I also have a problem adder header images. I use WPBakery as my editor but in both the default editor and WP Bakery, the same problem occurs.

We are wondering whether a recent Wordpress update/ compatability with the them has caused the issue. Can you suggest a solution?

Thanks
Calum Rogerson