Very good terms? More than that, the Queen was a member of the CoS and it is in fact part of the jiggery-pokery of the British constitution that the monarch changes their religious affiliation north of the border. Queen Elizabeth was, therefore, a Presbyterian when she died.
Also worth remembering that the monarch takes an oath to protect the independence of the Church of Scotland as their first official act after being proclaimed King.
More generally, I would imagine the King would have wished for other faiths to be represented - he did historically say that he wished to be the Defender of Faith, rather than the Defender of The Faith.
I expect that is inflated given it was supplied by a quack (sorry can't find the source but saw it on Twitter). I think it may be a figure of "everyone who would have had a reasonable opportunity to watch it". It was nonetheless an A++ grade world event, being the only thing shown on TV in my Swedish airport hotel yesterday.
Almost sounds like they got Professor Ferguson of Covid fame to provide the estimate!
But irrespective of numbers, I cannot think of a TV event that would have had this level of global interest. And of course events now will have higher viewing figures than historically, simply because more people have access to technology to be able to watch them. It is not like the days of the Queen's coronation when most houses did not have their own TV.
I found I watched far more than I planned to - I was going to watch the Westminster service then go our for a walk or bike ride in the afternoon, but ended up watching the full day's proceedings. Speaking to others this morning, that seems to be quite common.