Looking for a story

It's a regency ANI story, I remember the heroine goes to London disguised as a boy to inquire after her brother who is MIA/given as dead in the continent. She stays in a bachelor's lodgings with her other brother and a valet who can do practically anything from cutting hair to cooking and cleaning. There's a scene where the brother she's with strongly opposes to the valet giving his sister a "brutus" (which is cutting her hair very short).

There is also a lazy guardian who has only provided money for his charge (the heroine) and ends up marrying her.

Confusing summary, I know. Can you help?