These were originally given the reference code of W6 in our first reference book to the issues of W.D. & H.O. Wills. You find that whenever there is an actual Coronation of a King or Queen, many issuers bring out sets of Kings and Queens or Coronations. If you look at the side of the text on the reverse you will see that there is an arrowhead design, and this varies, so the set is usually described as having "wide" arrows (2mm across) or "narrow" arrows (1mm across). The cards with the narrower arrows are scarcer.
This was the first coronation to take place in West Minster Church (later to be renamed Westminster Abbey), which had been founded by the current King Edward the Confessor. When he died, childless, there was no immediate heir, though there were several people who could have easily been crowned the next King. However, Harold had already decided it would be him.
One of the reasons he gave was that his sister had been Edward's wife, so that was a blood link between him and the throne. He had also been busily spreading a story that Edward the Confessor had actually secretly named him as the one person that he wanted to follow him on to the throne. Then the moment that Edward died, Harold just said he was the new King and would not be dissuaded. Worst of all he then decided he would be crowned on the very same day the old King was laid to rest. This was not popular, as usually there was a period of grace and mourning between one King and another, and some times this was several months.
So when the text on this card says that instead of waiting for the Archbishop of Canterbury to perform the ceremony of officially crowning him, Harold reached over and just put the crown on to his own head, perhaps he was expecting the whole thing to be interrupted and cancelled at any moment. As it may well have been.