R7000 WiFi not broadcasting

I have an R7000 which up until now has been working really well.  Last night (at about 10pm GMT) the unit shut itself off (all lights off).  This morning when I looked at it I had to press the power switch twice to get the lights to come on again so I'm assuming that it was powered on even though there were no lights lit.  Since then the unit is not broadcasting WiFi.  We have many devices (phones, iPads, computer, laptops) in the houshold that use the WiFi and none of these can see either the 2.4 or 5ghz network connections.

The lights on the unit indicate that all is well; both the 2.4 and 5ghz lights are on and solid white as are the WiFi and WPS lights.

Netgear Genie says that wireless is off in the Basic tab.  under the Advanced tab I have red crosses against all four of the wireless settings boxes.  Wireless AP and Broadcast Name are both showing as 'On' but Channel is showing as '0' on the 2.4ghz box and is blank in the 5ghz box.

So far I have:

• Switched off the unit for ten seconds.
• Attempted changing the channels in the advanced settings (this made no difference and they are still showing as described above)
• Unchecked, applied and then rechecked the Enable SSID Broadcast tick boxes.
• Performed a factory reset.  I did not save or attempt to reapply the .cfg before doing this as advised on another post.

At the moment I have my computer plugged directly into the router and this is working fine.

Any ideas / suggestions would be very welcome.