Cannot restore / reset / SSH

I have been happily running ATV Flash on my ATV2 for a few months. however, I’ve had some probs with cache full / buffering on XBMC content.

 

Wanting to empty my cache, I tried SSH’ing the ATV. No joy, it wasn’t interested and neither cyberduck or Winscp could locate the ATV2

 

Having read a few confused threads I decided the easiest thing to do was to wipe the slate clean and start afresh

 

Expect when I try to restore the ATV to factory settings, I am given a message that this is unavailable at this time 

I wondered if it was due to me using unblock-us account, so chose to reset the settings, but even this does not work: the ATV crashes and does not restart without unplugging the power cable after attempting to reset the settings

 

Can anyone suggest what I night do to go about setting this thing up again from the beginning? I assume I have to restore the unit before installing flash again?

 

Any advice would be much appreciated