The English have had a solid yeoman class at least since the Black Death, and a middle class of minor gentry long before that. Your average yeoman-farmer's daughters in the 13th century were as modest as they could be. This tradition has continued. Jane Austen was not upper class - she was very much middle, daughter of a country rector whose brothers went into the Navy.
It's the upper class that has always been immodest in Britain - the real scandals in Jane Austen's period were generated by the nobility and royalty.
Yep, just look at the royal family.