When I had an issue with my previous TV (someone had left the mute on for hours and it pixelated the strip of the screen where the mute symbol runs down the screen) they sent out an engineer and changed the board. No charge to me and TV was good as new. It happened when the TV was under warrantee- but thought the service was brilliant.
Not as good as my mate who’s just blagged a brand new TV from Richer Sounds as a similar issue happened with the picture on his LG very intermittently. The TV isn’t bring made any more so he got a brand new upgrade and they told him just to keep the other one as well. Bastard