I didn't say it was "inherently fair" - I said it depends how you define fair. We all have a viewpoint on that, and they aren't the same. And the point is that not everyone does accept that definition of fair.
And do you seriously think someone that can afford a $45 million Gulfstream or a $100 million yacht would notice their taxes going up by £100? They'd need an accountant to tell them it had, and it would cost more than £100 to work out that it had.
But the point was .... what is "wealthy"? Or "high earner"? Is it £100,000, or is it a lot higher than that? And does it affect "fair"? What about removing the £6475 PA from someone earning £10 million a year? Or £100 million? Do you think they'll care? Someone ought to ask Richard Branson. Or, if he were a UK taxpayer, Bill Gates. Next time I meet either of them, I'll try to remember to ask.
I see nothing at all unfair in those that can afford to pay more doing so. The issue is where you set the line of "can afford", how much more they pay and what mechanism is used to do it.