Whatever else he did or didn't do, he was a UK diplomat who flagrantly abused his position and hung out with known, convicted sex offenders. Actions have consequences. And one such consequence is if you behave in such a way, you'll become persona non grata on the public stage.
His mother supported him, protected him, and likely put up the funds for him to pay her off. However, respect for her or otherwise is immaterial here. She's the one person who will neither know nor care.
Republic.org have, in recognition that some citizens will be upset by her death, stated the intention of maintaining a respectful silence until after the funeral. The protestors' actions are not, admittedly, a good way to behave in front of a cortege (not really a funeral) and my first inclination was that they were not doing the republican cause any good at all. Now that I've seen the heavy-handed approach by the police, I've changed my mind.
People are being tackled to the ground and bundled off in handcuffs for expressing a bona fide political stance. One woman was arrested for holding a placard reading 'Not My King' in silence. There were no profanities, no abuse, no public brawling. Freedom of expression has been under serious assault in the UK for some time, stifled under the pretext of 'hate speech'.
If these protestors - primarily the police response - raise questions about this as well as the future of the monarchy, IMO it will be no bad thing.