Well, that's just my opinion after listening to this podcast episode. E.g. the episode seemed to focus a lot on them and them being cleared which we all already know so why spend so long on the podcast on it? So this episode - building on the content from the other episodes - gave me the impression of it being PR exercise, 'we didn't do it, we had nothing to do with it, we did everything we could, this could of happened to anyone', PR to convince any doubters in the public. Which is fine.
Maybe it's just because this episode didn't really cover anything new so it feels like they are dragging the story out. Yes, and like you said, they were offered to participate so maybe this has nothing to do with them, I don't know how involved they are in the editing process, but yeah, that's still how I felt after listening to it.
And despite that, I'm still looking forward to the next episode! And I still think the podcast is good for William's case.