One maybe for @Leo when he starts travelling again, if he hasn’t already done it. The scenery where the line runs along the coast is worth catching - some glimpses in the last third of the video.
Agreed. I’ve traveled this route a few times and the section between Newcastle and Edinburgh is my favourite too.
Unfortunately you don’t see much of Edinburgh until you come out of Waverly station.
My advice would be to keep going north past Edinburgh and take the line all the way up to Aberdeen - the coastline on the approach to Aberdeen is spectacular!
There are a couple of trains out of London Kings Cross each day that go all the way up to Aberdeen, or you can catch a connecting train at Edinburgh.