A colleague and I tried to log in to NBN Gateway at the same time (on different computers) and each kept being told that we were logged in as ourselves, as the other person or not logged in at all depending on which page we tried to access. This also happened on other peoples computers within the council which was more than a little worrying.

I've been told that…

…the Proxy server was caching the web page we were viewing so the same page was being returned to multiple computers when the same URL was requested. It therefore appeared that we were logged in on multiple computers, though in reality we weren’t. Our IT department have now disabled caching for this website which has cured the problem.

Hopefully this might help a few others who are new to the gateway!