I am close by (Billingshurst) BUT an engineer has just been out and fixed it - the ONT box had failed - he had never seen one fail before and all lights on the box were green but it wasn't transmitting data.

All resolved now!

Good that it’s resolved. ONTs do fail from time to time, but they are generally pretty reliable beasts.

How bizarre! The right-most green light should flash when data is flowing, so that might have been a give-away.

I’m the dim distant past (OK 2019) I had an Ethernet port fault with a Huawei 1+1. From the outside it looked, and appeared to behave as normal. Except that it absolutely wasn’t and refused to negotiate link past 100BaseT. A lightning surge on the other part of the network may have possibly, maybe had something to do with it 😎

Openreach came and replaced it the next day. I was on a business connection at the time with Cerberus. Response was errr snappy.