But after the Act of Union of 1707 I am under the impression that England and Scotland were no longer independent Kingdoms and therefore technically William IV shouldn't have a different regal number in Scotland because Scotland wasn't an independent Kingdom at the time.

Having said that, I do think it was a mistake to continue with the tradition of numbering the Monarch s along English manner of numbering the Monarch.

In a perfect world George III of Great Britain should have been George I of the United Kingdom starting in 1801, beginning a new tradition of numbering the Monarch.

When I write in my blog about the King's or Queens of England, Scotland and Ireland between 1603 to 1707 I generally include both numbers. For example James I-VI and James II-VII and William III-II. After 1707 I do stick with the traditional English method of numbering the Monarch.

I had heard that to resolve the issue of numbering the monarchs of the United Kingdom, Winston Churchill suggested using whichever number was the highest number for a name of a monarch that had been used in both England or Scotland.

For example, if there is another King James he wouldn't be King James III of the United Kingdom, he would be King James VIII of the United Kingdom because there were more King of Scots named James.

I had wished Prince William had named his first son Alexander or James and we would get to see if this solution from Winston Churchill would have been used. I actually think a King Alexander IV of the United Kingdom sounds pretty neat!