Ah!
Ok. Now I get that part! Yes, sorry. With you. I am using the IP address (192.168.0.86)
Not 127.0.0.1!
SILLY ME!
Ok, I'll try it that way.
Sorry.....
(But it doesn't help explain why the MQTT dies when I unplug the cable. It is set to 127.0.0.1)
Just to add:
Changing the address to 127.0.0.1 in chrome and unplugging the cable, the messages are still going.
So that's good in some ways.
I'm guessing the script needs looking at. Though I did change the MQTT BROKER to 127.0.0.1 when I realised that a while back.