In order to solve this I connected to the console and:
delete osconfig
This command removes the OS configuration. It keeps policies, license and password. But it then restarts and asks you the original setup questions: IP, subnet, DNS, gateway, scanner and control center, etc.
After this I could connect again. As a test, I updated the host configuration (from the GUI of course) again, with an additional NTP server. And, voila, gone!
At the console I can ping my gateway and myself, but not another subnet. It appears to have lost its' gateway again. This would appear to be a bug.
Do I have to "delete osconfig" again to fix my network settings??? Has anyone else experienced this with 9.0.2? I am using a single IP.
Thanks
Paul