I read somewhere once that Joe Absolom looks like a cross between a young Malcolm McDowell and a meerkat, which is true, but he's putting in a great performance here. He's very intense and believable. I read this is the same writer that did Appropriate Adult a few years ago, which explains the quality of the dialogue.
As someone who works with PACE, I've been watching while cringing because I can see exactly where this is going to end up. I don't actually remember the case because I think perhaps it wasn't a prominent national news story.