'This was the point which The case hinged on. the prosecution couldn’t Prove beyond reasonable doubt that they knew which is why a manslaughter verdict rather than murder was given'
You keep saying this and I keep replying that in most crimes the offenders always say they didn't know/didn't mean it and the jury have to decide if they believe that after looking at the glaring facts presented. There's a case in the paper today of Wesley Streepe who said he didn't mean to murder his victim and his arm across her neck was accidental during rough sex. Fortunately that jury didn't fall for it and he's been convicted of murder.
Regarding the music, well yes of course they allegedly wouldn't have heard PC Harper shouting but surely far more obvious would be the lurching of the car as horrifically the weight of him would have caused the car to lurch excessively. Apparently though that would been completely normal to some posters here in an unfamiliar car! God knows why.
'Again, however, I expect I'm wasting my breath. Some people want to see them strung up and that's the end of it'
No, not 'strung up', just convicted of murder or given maximum manslaughter sentences. HTH.