This could be the root of your problem. Hubs and all routers are designed to be on 24/7. DLM continuously monitors your line and connection and could be picking up the disconnects as a problem and taking action.
You must try convincing her to leave it on.
Meanwhile the master socket is the best place for the hub to be. Could you also carry out a quiet line test on 17070 option 2. The line should be silent with a corded phone, with cordless you may get a background hum.
Hub now moved to different location and plugged direct into master socket.
How long till I would see a difference?
Provided it is left on hopefully within 10 days. As DLM relents you should see your noise margin reducing and speed increasing.
Did you try the quiet line test?