Just watched the tv drama and was lot of coughing overall going on and the audio tape produced as evidence had been edited maybe he was just proved beyond a reasonable doubt?
The TV drama did say at the start that events were changed for entertainment purposes, so don't take it as gospel. The 4 pagers were a give away. Who has, or had 4?
The jury thought they were guilty, that's all that matters.
That said, the light sentence passed makes me wonder if the defence put doubt in the mind of the judge.
Or, maybe; white, middle class people very rarely end up in prison?