Dual Monitor Issue in Windows 10

[iOFtheBEHOLDER]

I have 2 monitors for my PC, I use my TV as my main display, and have a secondary monitor for my second display, using windows Extend These Displays option
Sleep mode, screen saver, Turn Off Display - all disabled

When I use Windows + P to project on just my TV, the second monitor turns off because there's no signal and that's great, but then if I power off my TV for bedtime when I want to sleep, after a minute or so the PC will transfer the display to the second monitor which will then turn on.

How can I stop this from happening? When I turn off my TV I don't want the secondary monitor to then turn on and display anything, want that to stay off as well.
Could it be a TV setting causing it?
(I never had this issue since having my 2 displays, about 3 years now with multiple windows clean installs throughout that period, but this time a few days ago I just did a fresh install, and I have all the same settings I believe, or am I missing something obvious?)

[iOFtheBEHOLDER]

Ahh I seemed to have solved it myself, newer smart TV's normally don't shut off, they go into a low power mode when pressing the power button to turn it off.

Seems for me my TV is not going into low power savings mode, and shutting completely off, I noticed when turning it back on while troubleshooting, that the Logo was coming up, which shouldn't unless it has been unplugged or holding the power button down to restart the TV and the Smart OS.