This is much harder to evade - if you own most of Mayfair, you can't just move your assets elsewhere - they are very clearly tied to the location.
Of course, this would mean taxing powerful aristocrats, including the royal family. With their large majority, the British government had the opportunity to do this, but decided to take an easier path. The reason why this path was easier is now becoming clear to them.
There was a bit of a scandal a few years back at just how much input the Queen got to those sort of laws, but it didn't really have legs as everyone thought she was brilliant.
But if the same thing comes out about King Charles you can bet it's going to be a bigger stink.