If you gave an indication of the location/town then people may be able to suggest which network it is, and then you could check on their availability checker.
A fibre can go "under your road" for many reasons - it may a leased line to another (distant) property, or part of a third-party provider's backbone network.
It may already be "activated", in the sense that it's carrying traffic. It doesn't necessarily mean you can order service for your property.
If it's a third party network then you may be able to order a business leased line type service from them, and the fact that the cable goes close to you means that you won't have to pay Excess Construction Charges - but you would expect to have to pay £150+ per month for this type of service, on a 1-3 year contract.
There are very few networks apart from Openreach which wholesale to other providers: Cityfibre is the main one, Gigaclear does some too (but only with small and relatively unknown resellers). So you're right to say that if this is a non-OR fibre, chances are you wouldn't be able to continue to take service from your current provider, whoever that is.
Edited by candlerb (Tue 16-Apr-24 10:45:19)