It was strange for me for other reasons:
Every raspberry pi "didn't exist" i.e. couldn't list their IP's nor could I ping them ( everything else existed though ).
I haven't rebooted any pi's before or after the event.
Blu Iris must of been running as it was triggering lighting which means the ip camera must be working and indeed homeseer z wave was working to turn the light on.
So it was like everything is working but you can't access anything.
Don't like these situation especially when magic fixes them. Have ordered a portable HDMI screen so at least if it happens again I can plug that into the HA pc as it's headless. If that ever goes down ( it hasn't; but windows always decides to do an update at some point ) then we have no lights, no heating, no audio etc. etc. SWMBO approval factor then drops rapidly!!