SWMBOs lifeline is an iPad Pro (big screen for f***ed eyesight).
I've just spent 30 minutes messing around because it "stopped working" ..
For some reason, despite claiming to be connected to the same WiFi AP as for the past 2 years, it couldn't see the internet.
Everything else on the network can.
Tried resetting the iPads network settings. tried rebooting the router.
No joy.
Changed the SSID on the router and connected to that. Bingo !