Default admin login gets lost when add a non-admin staff user
When installing I set up a default user/password as prompted, and used this as the admin login while testing.
Then I added a staff user with a different user/password and set the Account Type to Staff and not Admin.
Once I'd done this the initial default admin login was no longer valid, and, of course, I no longer had access to the admin panel!
To fix this I used phpmyadmin to do an online edit of the staff user's record in ost_staff and changed the value of "isadmin" from "0" to "1".