It's utterly tragic.
I don't know the town but from the video and photos, I'd say it looked an awful lot like a pavement. Cyclists shouldn't ride on pavements, and pedestrians who don't want cyclists on pavements are not "territorial" - they're legally right.
It should be easy to tell if something is a pavement or a shared cycleway. It's shocking that the police couldn't agree whether this was indeed a regular pavement or not - they had time to research this. The fact they couldn't decide shows there is something very wrong with the town planning, making this an entirely preventable accident. If the police with all their resources don't know after spending time on the matter, how is a visually impaired person supposed to tell from a quick glance?
It doesn't look to me like Grey actually pushed the deceased, just scared her into veering off, but the detective who interviewed Grey did say that there was more CCTV footage that had not been released. Maybe it's clearer from that. This whole thing has gone to court, so there must be details we don't know about that make this more clear-cut.
Without seeing those details, I can't say if I believe this should have been manslaughter. It could just have been an accident. It's abhorrent that Grey apparently didn't call 999 and show remorse, but is that in itself a crime? There's a crime for not stopping at the scene of an accident, I think, but isn't that in relation to drivers? Being unpleasant isn't in itself a crime.
I feel for the victim and her family, and for the driver, and to a lesser extent, for Grey. All three of them had the right to safely travel from A to B that day, and this set of circumstances should never have been possible. The town planners have a lot to answer for. I think they need to look at cycle options and signage urgently.