Well, this amongst other things. Part of the problem is police with only the remotest idea of what the rights are that they are supposed to defend and uphold, combined with the notion that 'making a fuss' is a public order offence.
More evidence from the signing during the Privy Council meeting (i'm sure there's a better way of describing it!). Prior to this was a fairly passionate speech from KCIII braying about following in the Queen's footsteps and being a paragon of duty, carrying this out with love and humility - then shows signs of all out autocracy in these little asides, which are undoubtedly snippets into the true personality behind the scenes.
I get the dude's under a huge amount of stress, pressure, is at the sharp end of the grieving process and was given a tiny table for signing some comical large documents, but still, there's better ways of treating the staff. :C
To be fair, he may not be aware of how those expressions appear, and they may not reflect as extreme an intention as they seem to. I remember watching back some video of when I was cat-herding my kids when they were about 4 and 8, together with a couple of their little friends. It had been frustrating, but not especially unusual or difficult, but I was horrified by the range of expressions on my face which were more like paroxysms of fury than anything else.
That said, he's got previous, and he's just behaved unbelievably badly to his Clarence House Staff.