Bad documentary or miscarriage of justice?

Finally got around to finishing this, and I have just been stunned by it. From the outset, I'll say that I genuinely do not know whether he is guilty or not - the injuries seem suspicious for a fall, but multiple experts said they were plausible so they know better than I do.

However, what I do know is that nothing I saw in the film could add up to a guilty verdict. Nothing. The defence proved early on that the crime scene was contaminated and the evidence was not to be trusted. They made fools of Deever and the detective they interviewed. The prosecutions concept of the blowpoke was destroyed, they showed no feasible more weapon, they did not give any credible account for what they believe did happen, it was clear even before the additional episode that the "experiments" were utter nonsense, they had experts to dispute the autopsy findings... How does that not add up to reasonable doubt? I didn't see either side give a plausible explanation for what happened and, in a court, that requires a not guilty verdict.

Initially I was stunned and disgusted by the jury. But then I saw the additional Storyville film and was stunned to hear that all his appeals were overturned. I just cannot see how that case could end up with this result.

My only conclusion at this point is that vital evidence or testimony was excluded, because a unanimous guilty verdict and multiple overturned appeals in a case where nothing at all is proven makes no sense to me.