Drawings 66 to 71 show the approved design. As construction began before the end of November, these drawings were probably made in late November. The design for the new wing varies from previous designs mainly by the positioning and shape of the drawing room (here unlabelled), a three-bay room centred on the south front and having segmental ends. The room is set between two identical ranges, the east range containing little more than a facade and a stairwell. The plan of the wing circulates around the existing tribune, with doors on three sides and a chimney-piece occupying the north end. The proposed plan does not introduce any striking enfilades or axial arrangements; rather, the existing enfilade through the breakfast room and tribune is disappointingly misaligned with the chimney-piece centred in the east room. In later designs (drawings 72 to 74), this misalignment is slightly reconciled by the inclusion of a wider door frame opposite the chimney-piece.

The new wing has first and attic floors over the east and south ranges. The existing single-storey tribune is not obstructed by these additions so that it remains top-lit. Four bedrooms are in the new wing and are accessed from proposed staircase (drawing 70). A communication between the existing house and the new wing on the first floor does not exist. The attic storey is shown with three bedrooms in the proposed wing (drawing 35). The design for the staircase is unfinished in these drawings.

Drawings 67 and 69 have been altered in rough pencil to include a wing on the east end of the house, having both a basement and ground floor.