That does look awesome! What is the silver circle under the telly?

Same point though, if you change telly what will you do if the power supply is different? Just cut the plug at the TV end and replace it with the new one?

That method you used might be the way to go, assuming I can get the wires going horizontally along the plasterboard wall without hitting wood! Or I drop it to the floor and go under the floorboards and back up!

Where do your ariel, Scarts go to or are tey out of shot? At some point the ariel must come out of the wall to plug in?