A couple of questions (SPOILERS!)
1) At what point did Lady Susan become pregnant?
2) Why did she go back to London and leave her daughter at Churchill?
3) Why did the Vernons want her daughter for Reginald? They could have found a young lady with education, beauty and wealth (and less baggage) for him.
4) What was different in the book (which I have not read). I understand that there is no pregnancy in the book, no Manwaring living with them... So what are the driving factors and does it only end with her marriage to Martin and her daughter's marriage to Reginald?