Hi Fergal,
Thanks for your feedback.
Currently, our plugin does not change the default menu structure, it just fills the position of a menu between the default positions of WordPress which you can see here https://developer.wordpress.org/reference/functions/add_menu_page/#menu-structure
2 – Dashboard
4 – Separator
5 – Posts
So that means only 1 menu can be inserted between Dashboard and Separator. Hope that makes sense.