You can't make a silk purse out of a sow's ear ...
... PN can only supplty FTTP if the cabling is in place.
Not quite. It seems they can't supply it even if the cabling is in place. Or rather, they've chosen not to supply it, other than to those of us who are fortunate to already be on the 'now-closed-to-new-entrants' FTTP trial.