We wanted to give you more insight into the matter, but blueacid and MrSaffron responded as good as we would have - thank you guys! We use our own infrastructure, and require no telephone exchanges to distribute our service.
Currently, fibre is brought to the basement (in most cases) of a building we are servicing, where our network equipment is installed, and distributed through the building and onto each floor via Cat5e/Cat6 cables.
Once the Ethernet cable is in your flat, it is terminated into a network socket, to which you would be plugging in a router.
If you have any other questions, we would be happy to address them.