You'll find that this story has many twists and turns and never goes quite the way we think. This story is all about Tommy and how war changed him. We get glimpses of the pre war Tommy, romantic, sweet when he is with Grace, do we ever see Tommy smile when he is not with Grace? Your reaction to Arthur was just like mine we all love Arthur and it was the longest seconds ever before that rope snapped.
Jut in case you were unaware their Dad is Polly's brother and Polly looked after the children after their Mum died and then their Dad left them.
You said the Grace Campbell scene was strange but all the way through the season he has been touching her hand in an inappropriate way and his relationship seemed too creepy for it to be just professional, so although it was a shock to see him propose it actually made sense and yes it gives another big reason to hate Tommy and want to take him down. Loving your reactions!!!!