Hi Colin,
Thanks for helping me out with this. Seems I have discovered reason, and fixed it, for configuration being "Unknown", controller had a separate entry for different AW appliance (not in use anymore). Configuration is now showing as "Error", and when you click on device link it says: "Error (Telnet/SSH Error: Could not fetch config file; command timed-out)".
I am sure that my SSH details are OK as I just used putty on both controllers in order to verify. There is a post from earlier today with same error message appearing, but no fix suggested. Thanks.
Alan