How do you get Alexa working with an Ld Oled TV?

[RobGardner]

I have a 2020 Lg C9 TV and I can’t control the TV using an Echo dot. I did once manage it for about 5 minutes after hours of logging in to this and logging in to that, but once I switched the TV off it all stopped working. I usually turn to YouTube to find a suitable video but the only videos are not about UK models so the guidance is not an exact match. Has anyone managed to get their LgTV to play nicely with their Alexa?
Now even using the remote control microphone isn’t working.