The correspondants to that thread above gave you most of the info you needed. However,
1) I don't believe its right that any wayleave agreement for poles will be found on your land title.
2) The people in Shrewsbury should be willing to tell you if there is a wayleave.
3) I believe that electricity utilities do not put wires on BT poles, and BT are within there right o demend it be taken off if there is a wayleave in place. The reverse (BT wires on electricity poles) was quite common but the Utilities have stopped BT installing any more like this. A SSE engineer told me it was because an engineer was electrocuted off a linked pole.