Maybe Ed was scrambling through the grounds of the house stalking her, hence the grass stains on his jacket, and maybe he saw something. I agree with this; it's too obvious that it would be him. I think there's still something to come out about his caravans/seasonal renters. Although they haven't revisited that idea since Ellie brought it up a couple of episodes ago.
Joe got off as his lawyer argued Ellie beat the confession out of him. I'm not sure about this. I thought she kicked seven shades of shit out of him AFTER he'd confessed?
Katie may well redeem herself; it would have to be something dramatic, but then again that would make for good drama 
I don't understand why Cath would agree to stay and move away with Jim, when even before she found out about his having sex with Trish she described her relationship with Jim to the police as "loveless”. I don't either. Is she just so ground down/trapped that she can't see another way?
Has it been established who rents the property near the crime scene? No. The cops went to it a few episodes ago and mentioned that they hadn't tracked anyone down. They seem to have dropped this thread for now, which could mean it's set to come back up again in a big way.
Have we seen much of Beth's baby this series? I thought it was
Chloe's? 
Didn't she, Beth and Mark have a conversation about how proud they were of her for going back to her studies after the baby was born?
I am leaning towards the rapist being Jim. He could have been the breakdown service that didn't turn up –except he DID turn up, saw that the woman had abandoned her car and was walking, and took advantage. I wonder if Kath knows about this and that's what she said she could tear his life down about?
I can't quite explain the other rape though, of the woman who was walking home from the pub; I wonder if that was the taxi driver and he was/is in the habit of hanging around pubs and routes leading away from them, expressly to be able to prey on women walking home drunk and alone?