BT will always attempt to route any overhead lines in such a way that provides the least inconveniece to all concerned - routing wires past people's lounge windows does not fit into this remit.
You will find that BT will send a Survey Officer in advance to see which way is the best to re-route the line concerned. They may elect to run it underground - unlikely as this is more expensive than overhead, so the most likely option is a re-route via other means.
No need to panic - look around and see how many other people in your road have lines across their windows. It just doesn't happen.