looking for a title

[Amanda]

I am looking for a signet regency romance book. The author wrote a series about sisters, each book about each sister. This particular sister was the wild child, the hoyden. They are on their way to London for the season and she is riding her horse by the carriage. They stop at an inn for the night and she somehow witnesses something terrible and to hide herself, she begs a gentleman to kiss her to disguise that she was a witness. He demands to know what is going on and she explains everything afterwards. Turns out he is a lord (duke or marquess maybe?) who is a rake and everyone wants him. He follows them to London and ends up saving her from all kinds of scrapes and problems. In the end he falls in love with her and drags her to Gretna Green for marriage. She begs him not to marry her because she thinks she isn't good enough for him.
Any insight on which book this might be is appreciated.
I know that the same author wrote another book about another one of the sisters, this one who is sickly and was in a carriage accident and spends most of her time in Bath.

[Lesley-Anne]

Could this be the Marion Chesney series called "Six Sisters"? I'm sorry I don't know which of the series your book might be. It's a long time since I read the series and I don't have clear memories of the individual books. Chesney is always a lot of fun, though! Hope this helps a little...