There could be any number of reasons why that is the case. The routing of BT cables from a house to the exchange is dependent on how the phone is connected to the overhead or underground cables. Just because two houses are close to each other it doesn't mean that the wires take the same route to the exchange. If the BT site says that's what you'll get then there is very little you can do about it (apart from moving house of course!).
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Do you know that we're all in line for succession to the throne? Really?
Well, if forty-eight million, two hundred thousand, seven hundred and one people died I'd be Queen.