Ethernet Profile won’t configure correctly

Hi

I am running 17.3 on Q Box with Android 5.1.1
I started by using WiFi to configure the box (I was missing a long enough ethernet cable) and all went well.
I then plugged in the ethernet cable and ran into difficulties.
I probably should have stopped the WiFI bewfore I plugged in the ethernet but…

Essentially the IP configuration is missing the Gateway address.
So I get “Web Page not available” and of course nothing links up.

I tried using static settings but no way would it recognise the settings.
I mean that the settings were accepted but when I checked on system information the Gateway value was blank.
All the rest was there, IP, Sub-Net Mask, DNS Servers…

So of course I cannot browse or do anything.
I have backed up Kodi so I could try a Factory Reset but before doing that I am hoping that someone can point me in the right direction.

Thanks

Kris