As many others have said, it would have been better on a different channel and not the BBC. Showing how the BBC didn't care at the time about his victims, and they don't care now, not giving the victims much more than probably a grand total of 10 minutes over all episodes. And focusing on him and the interviews.
The only good part is Steve Coogan, who portrays him like it was actually him.
Does it add anything to what we know? No. Does it do justice to the victims? No.