I have removed all my vQmods and manual changes so my entire install was identical to a fresh install on a file by file basis which only leaves the database...and I don't have any experience to go messing in there! Having thus eliminated any of my other mods I was still left with the problem:
When Access permissions are limited at all then Users get a Permission Denied error inside another frame when editing products as shown below:
So if you wanted to use the "Hide Admin Menus" based on permissions vQmod by Giuseppe Davi you would effectively "break" the edit products page (although strangely it does still allow users to edit and save them by scrolling up and down past the Permission Denied message).
To get round that I have made a slight change to Giuseppe's XML file and removed all 60 instances of 'access' and replaced them with 'modify' so that OC is now checking for Modify permissions when hiding the menus - as the Modify permissions still work as they should, this workaround allows me to still hide Admin menus from the less-IT literate end-users and creates a tidier admin panel for them.
Maybe no-one else will have this problem, but just in case I thought I would share my solution

Stokey