Manage Term Creation in Taxonomy by role

I have a created a taxonomy field. However I need to allow users with a specific role ‘expert’ to create terms, without adding the capability ‘manage_categories’ to the role, as I don’t want the role to have access to edit terms in other taxonomies.

I can not find a way to allow this without adding capability to the role for ‘manage_categories’.

Does anyone know a way or filter which will allow me to edit the capabilities required to add terms for a custom taxonomy created using this plugin, without adding ‘manage_categories’ to the role?

Ideally I can create a new capability ‘manage_categories_custom’ and somehow add this to the settings array for this custom taxonomy?

Any help would be much appreciated.