I didn't think the grilled cheese looked that bad. A little bit of char on the one side of the crust hardly makes it unappetising. Tbh you can't really tell how melted the cheese is. Sure it's not oozing, but you're never gonna get there directly over a fireplace with thick slabs of cheese. I wonder if this is a UK Vs US thing? It's not too uncommon for cheese in a burger to only be semi-melted in the UK.

Agreed. The two important things with a grilled cheese are

1. Crusting up and cooking the bread. You want a good texture and maillard reaction for the bread flavor to come out.

2. The cheese to be warmed up and softened to bring out it's flavor.

You don't actually need to cheese to _melt_ fully. That is just aesthetics. And the bread in the video was only just a touch overdone, really not meaningful. I'm not sure the video actually is a mistake at all.