Unless you can root out undiscovered plans or photos of that area from somewhere on the net.
I must admit I haven't looked at all the floor plans yet.
The main floor - ground floor.
the butler pantry was half a floor lower than the ground floor, so the section must have been sloping.
The basement is one floor lower than the ground floor.
The steps at the end of the Butler Pantry take you up, less height than you have to descend from the spiral staircase end. So there must have been a floor area half way between the pantry and the kitchen.
Second floor were the children's bedrooms.
Third floor were the parents bedroom bathrooms etc.
So above the ground floor it is less complicated.
Kitchen, living room etc = level zero.
Toilet and washroom down stairs towards basement = level -0.25 (a quarter of a level down)
Butler pantry = -0.5 (half a level down)
Then the basement = -1 (full level down)
So in my way of thinking that house had 6 different floor levels.
from lowest
1. Basement,
2. butler pantry,
3. toilets and washroom,
4. Kitchen on main floor etc.,
5. Children's bedrooms,
6. parent's bedrooms.