The plans and elevations for the stables (drawings 14 to 17) have running dimensions, suggesting that they could have been made to estimate the quantity and price of bricks required for building. Soane had previously presented designs for the stables in January 1789 (Journal N^o 1), and so by December an estimate was probably in order. Soane visited Mr Watson on December 14th 1789 with fair drawings showing a plan and two elevations of the stables (Journal N^o 1); drawings 14 to 17 therefore could be preliminary designs and drawing 18 could be one of the finished presentation drawings (the misspelling of Mr Watson's initials may account for it being left behind with the design drawings).

The designs for the stables at Lees Court show a quadrangular building with external dimensions of 102 feet by 123 feet 9 inches, with the entrance projecting an additional 14 feet 9 inches on one side. The side and rear elevations are articulated by round-headed relief arches evenly distributed, at 11 feet 10½ inch intervals on the side elevations and at smaller intervals at the rear front. The arched entrance leads beneath the clock tower into the stable court (81 feet by 57 feet 7½ inches) to face a double-height rounded arcade. A ride occupies the area beyond the arcade and is lit by large Diocletian windows on the first and ground floors. Facing the ride is a series of stables. Without any windows, the light is somewhat deficient within these stalls and a note on the first floor plan (drawing 15) suggests 'AA these floors to be / framed to admit / light into the stables'.

Corn stores are on the first floor at the front and back ranges, with an opening in floor over the entrance 'for craning up corn out of the waggons' (drawing 15).

The ground floor plan (drawing 14) has erasure marks for alterations to the narrow windows within canted alcoves at the four corners of the arched entrance. Erasure marks also occur at the blind windows on the rear elevation.

The buildings' chimneys are shaped as urns, with smoke shown emitting from them in the elevation (drawing 16).