Done some more investigations.tp link AV1000. One adapter downstairs connected to back of router. One adapter upstairs connected to my security camera system. I swopped the adapters around. With the uptstairs one plugged into the router downstairs, and the upstairs one not plugged in. The broadband test says all is well. I then plugged the upstairs adapter into the power socket, without the LAN cable connected. Did another speed test. All ok. Plugged the LAN cable into the camera system. Did a seed test, nothing. I think this says that one of the tp link units is faulty, i think?