I have a BT 4k youview box and is connected via ethernet, but it appears to be giving off wifi as well BTWi-fi and BTWiFi-X. (even with the BT router switch off I can still see it and its not my neighbours).
I have a complete Unifi AP network and I can see it jumping channels all the time which is causing small issues with my wireless.
Has anyone seen this and manged to disable it, I can see anything in the menus ☹
What leads you to believe it is not emanating from your neighbour?
Does it disappear if you switch off the YouView box, I suspect not?