I am not sure whether they identified the source or not. They told me that they had made an appointment to visit the property that was causing the problem, but the the owner refused to turn the equipment off. I have asked my ISP to get some more details but they are refusing to release this information.
I do not believe that only my line can be affected so have asked via my ISP to find out if anyone else is having the same issue. I have spoken to a neighbour who is closer to the source and to the exchange and they are not seeing an issue.
The problem is that BT have diagnosed it as a REIN issue and as the owner of the source is refusing to switch it off there is nothing more that can be done.
This is the latest graph
My Broadband Ping