You should have seen what the people did who replaced the old Windows. They wedged the cable around the side of the Window frame then cut a hole out of the trim to fit it around the junction box.
If anyone asks I did NOT disconnect it, drill a hole through the wall and wire it back up directly into the master socket.
Funnily enough, BT contractors later came round and applied silicon around the hole, presumably assuming the contractors had done it.
Kelly Communications have inspected it since as I temporarily had a second line fitted by Origin Broadband.
Someone else I know I believe they completely disconnected the master socket as when they had done it had been screwed back on the wrong way around and there was no dial tone. The latter might be a coincidence though as it was an inactive line but had previously still been getting a dial tone.