I don't mind about the Home Sec thing - I think Harry knows that it was not personal and that, if he had been a traitor, that's exactly how he should have been treated.
Ros was apparently dead then wasn't and was seen disappearing through the graveyard at her own funeral.
Then she appeared in Russia on a deep-cover thing near the beginning of this serise ... it wasn't explained but it did tie in with the story line at the time so it didn't grate quite as much as when they've done it in the past.
Do you remember the end of the serise when Tom Quin's girlfriend and her daughter were in his house which was apparently about to blow up? The next serise began about 2 seconds after the last one finished - much better IMHO.