Oh dear, I was so looking forward to Imelda Staunton's version as she is a great actress but her version of A Lady of Letters seemed very flat to me. Patricia Routledge's lady had so much more light and shade. From being irritated by her initial nosiness, pomposity and lack of self-awareness , by the end I felt so sorry for her.
Sarah Lancashire was brilliant but I don't remember the original. It was rather a strange subject and uncomfortable subject. I haven't heard of mothers being sexually attracted to their sons or, as she said, "in love" but SL was, in my opinion, certainly very convincing in the part.
I couldn't see the Thora Hird cream cracker under the settee one listed. That was probably the one that struck me the most - and Alan Bennett's one about his monstrous mother.
I sometimes wonder if Alan Bennett based these characters on people he had come across in real life or if he just has immense creativity and imagination.