I don’t understand why u want to close the thread.
I understand you have given me as much as advice as you can but surely someone knows what they are doing and how to stop them from doing it. I know your not employed by BT but this is not the right way to behave.
even after changing my WiFi passwords and even turning off the WiFi on my TV and removing the power line adapters they are still able to cast my tv screen onto their device. They are either doing this directly from the ps4 or bt box or through my TV. But if they were doing this through my TV I would have known.