You've put your finger on the things that bothered me about Season Two - I didn't like Christine, and the finale did come out of nowhere. (Mind you, Tom's love life in general is my least favourite part of the whole show, I think.) I spent the long, long gap between Season Two and Season Three hoping they wouldn't explain Harry's behaviour by having him be the one who set Tom up. (Fortunately, they did not.)

I missed Tessa, but I do love Ruth to bits, especially in Season Three. (I have yet to see Season Four, due to being a deprived antipodean.) If only we could have Tessa and Ruth at the same time.