I need a tab, only accessible to admins in the backend.
Accessing the 'comprofiler_tabs' directly from a database client (phpMyAdmin etc.) set the 'sys' field to 1 in the row for the desired tab.
It seems that this stops the tab from being viewd in profiles etc. However, it can be viewed from the 'user management' system in the backend.
It would be nice to have this as a built-in feature though eh ?
Hope this helps someone.