Apple TV black box on screen and remote not working

Hi, I have an Apple TV 2 (tvOS11.3) it's suddenly had a black box appear around the apps on screen and is saying the name of the apps - but the most frustrating thing is the remote (both actual remote and ipad app) won't track properly over the screen. They stick on random apps or skip over apps/levels of the settings menu completely. For instance, I have read some of the answers here and it suggests I go to General/Accessibility to fix the box/voice, but the remote/ipad app will not track down to Accessibility to allow me to even view the problem. I have the remote and ipad fully charged.

I have tried to reset/repair the remote which didn’t help. I've tried to reset the Apple TV and it told me it was going to change screen resolution.

Anyone have any ideas how to fix this? All input gratefully accepted.