TBH, you have already had an explanation from OR, your property cannot be served from the nearest CBT. You haven’t answered if your current copper service is delivered overhead or underground, assuming it’s underground, the closest joint box with a CBT ( and assuming a spare port on that CBT, the network is ‘sized’ for the location, if the CBT was designed to service 8 houses , an 8 port CBT may exist, so there may already be no spare port available, ).
Its also possible that the box the CBT is in, isn’t linked to the box closest to your home, and your home , even if underground service , may be a DIG cable ( direct in ground ) so to get fibre to your home may need duct work to connect the CBT box to your box, then duct from that box to your home, and more network construction ( the CBT that exists is too far away to be any good to you anyway ) so possibly a new box required to house a new CBT , this as you may suspect could well cost many thousands of ££’s, and if you are the ‘only’ resident bothered, then that type of expense won’t be entertained for one customer.
If, ( for example ) the CFP network cost was £10,000, it’s probably too much for one person to consider, but if you had 19 like minded individuals , they ‘may’ consider £500 each to get better broadband, if not you really have no choice but to wait until the area is naturally covered ,or the government effectively steps in with the £10,000 via some sort of subsidy in the near future.
The ‘route’ you assume the fibre runs, even if accurate , is irrelevant, if a fibre cable runs straight through a box , and that box is close to you, it’s no help, as a poor analogy , if you could see a motorway 200m from your garden but the closest slip road onto that motorway was 10Km away, then to get onto the motorway that 200m is irrelevant, you need to drive the 10K, just because a cable runs through a box doesn’t mean access to those fibres is available...to give service it’s a CBT required close enough to you, not a cable.
