Wot if you live in a flat already?
From Openreach's FTTP page:
Multi-Dwelling Units (MDU) and Multi-Occupancy Units (MOU)
We recommend that you discuss the property type with your end customer to establish whether their premises is a multi-dwelling unit (MDU), i.e. apartment block, or multi-occupancy business unit (MOU), prior to the order being raised. Any orders received for MDUs or MOUs will be rejected.
What's the betting that this applies even if the flat, like mine, is on the ground floor with its own private entrance. The existing Openreach copper line appears out of the ground next to said door, up the wall in some capping and through the wall into the hall. It doesn't run through any shared/communal areas of the block.