Totally agree with this: I was scrolling to the end to make a similar point. Becky might have liked TLR and enjoyed spending time with him, much to the horror of her mother, but none of that means he didn’t also brutally rape her. We’ve also seen plenty of evidence that he is capable of vehemently denying crimes we have seen him commit.
The letting Ryan walk home by himself plot hole is like the prison letters/visiting one in this. So staggeringly unlikely, and clearly done entirely for plot development, that I have to determinedly NOT think about it! As for Catherine being slow in series 1, DH and I were actually laughing at how dim she was about joining the dots, but I also wonder whether it might be more realistic than the usual lightning-fast detective trope? Still stood out in a drama though.