Drawings for the offices were sent to the client on 4 May 1790. Drawings 2 to 5 are probably copies of the design. Soane's Journal No 1 records that working drawings were taken to the site on 12 May, perhaps drawings 2 to 5. As drawing 6 shows, however, these are not the final built design though the layout is the same as the executed version.
The offices extend east from the house. The plans on drawings 2 and 3 are unlabelled but if one may assume that the building contains the same ground floor rooms as Soane's labelled preliminary design (drawing 1), the central passage leads to a servant's hall and secondary staircase before descending a quarter-flight of stairs past the housekeeper's room and then out to a covered passage that leads to a single-storey range with a kitchen, scullery and larders. Upstairs, the first floor has six rooms resembling servants' bedrooms, each having a chimney-piece, and another staircase to the attic. Only the middle two bays have an attic floor. On the south elevation, the first floor windows on four bays are surrounded by round-headed arched recesses. On both south and north elevations, the centre two bays have a string course between the first and attic storeys, and a cornice above.