> that dynamic would usually imply (to my mind) a trusted person in charge of the staff in their absence, to contact, not the two persons combined in one.

Exactly. Although its a touch shameful, the first thing that went through my mind reading the story in the comments was "what kind of person has a mansion and only one maid?".

Multi-room houses aren't easy to keep clean. Add cooking, driving, and shopping on top of that and we have a situation where:

(a) Someone is being severely overworked

(b) Someone cannot keep up with the work, leading to frustration on the employers part and an unnecessarily bad relationship