Question about the Nave area

[Margaret]

I just had another look, and still can't find it. There are two sets of stairs, with a walkway connecting them and a number of cells. At the top of the stairs at each end is a table and chair. One of the tables had something on it that was needed for a potion. Is this the right area? Because I can't find any doors except to cells.
Sorry for being a pest, but this is bugging me.