When VM did fibre a fibre extension in our village (about half the village had fibre installed by Telewest 20 years ago, the rest of the village is new houses that have appeared since), very little showed up on One Network - they came to do an inspection of the Openreach ducts that they ran their equipment through and the only things that showed up on One Network was where they found a blockage, but as so many of the houses here are new then very little work was needed.
Only sign I got that VM was coming was some green markings left on the Openreach covers that the inspection team left and you can find a thread I created about 6 months ago, detailing all of this.
Essentially, if your ducts are in decent shape, you won't know they are coming until the contractors start laying the fibre to the junction points they are using and then when a customer orders they run the fibre back to these junction points, so my nearest one is about 100 yards away and when my neighbour had VM installed they just ran a cable using the openreach ducting to connect him up.
