@RobDuggan Welcome aboard
The reason you should not post in old threads is because the answers become confused and NO ONE wants to read through a thread with a large number of posts to try to figure out what is going on. So, if you find a similar answer, rather than posting in the thread, start a new one and post a link to a partial answer and tell us what else you need.
I don't use the navigation form myself because it is too awkward to always be working with a subform and it interferes with my ability to use the open form method and pass in selection criteria and the open args. So, I don't like the way it works. I also don't want to "hard code" my menu. The form looks nice and if you have a small app with fewer than about 20 options, is is useful. But it does not scale well and you cannot nest navigation forms. The problem with hard-coded anything is it becomes a PITA to change. Always look for ways to tableize your workflow. It is ever so much easier to change a table than to change a form and have to move stuff around to fill in the gaps.
Call me old fashioned but I still like the switchboard style. I've updated mine to enable more than 8 items and even created totally new versions but that is my go-to menuing interface just because it is so easy to work with. My clients don't pay me to make stylish, complex interfaces. They pay me to make functional applications that someone else will be able to maintain once I move on. I make them pleasing to look at but functionality comes first. Cost comes second. "Slick" is nowhere in the list.
I have two sample databases with several options. One of the databases includes a minimal security option and the other is no security.
This Switchboard form is based on the last VBA version which I think was A2k. I expanded it to allow for 12 items rather than 8 and you can easily change it to do more. I've included directions. This updated version has two switchboards. One more traditional and the other is big buttons...
www.access-programmers.co.uk
This is a custom switchboard. It expands on the Switchboard Items table to add four additional columns to define view/edit/add/delete security levels for switchboard items and forms/reports referenced by them. It includes tables to manage users and also to assign them security levels. The user...
www.access-programmers.co.uk
It is probably too late to help with this app but they are something to think about going forward. The alternative, if you really want to stick with this style is to make your own navigation subforms. I don't recommend this though. The reason the navigation form doesn't nest more than one level is it just gets too hard to manage with a generic interface. If you code a custom interface, you will have more luck because your code is custom rather than generic.