Thought it might be that and while I think that the idea of focussing on the servants was a good idea, I think that what made UD special was the focus on BOTH parts of the house. I Dont think it would have worked so well if they had kept to a main focus on the servants' lives esp if Sarah had remained as one of thte important characters. She was an annoying character and just did not fit. I wonder if they realised that and wrote her out, though she did keep coming back (rather improbably at times).