I have my permalink structure for posts set up like this: /%category%/%postname%/
This generates URLs like this: mysite.io/category/sub-category/post-name
Thats all fine.
However, the archive page URLs for subcategories are like this: mysite.io/sub-category
Instead, the URLs for subcategories should be like this: mysite.io/category/sub-category
This category type is actually a custom taxonomy registered by the parent theme. I don't think it is possible to use the permalink settings in the admin dashboard to change the URL structure of this but perhaps there is something I could add to the functions.php to alter the registered taxonomy?
I have found this page in WordPress codex and think it might be useful for finding a solution but my WordPress knowledge seems way too limited to understand how:
'hierarchical' - true or false allow hierarchical urls (implemented in Version 3.1) - defaults to false
Function Reference/register taxonomy
Thanks in advance