Birkenbridge is the residence of Colonel Watson, and the temporary address of Mr Graham, Mr Hammond and other soldiers in his regiment. Its staff include a housekeeper and Sarah, a maid, as well as the Colonel's two beloved hounds. The estate also includes a garden that the Colonel tends for himself, which has grown a little wild in his absence.

The kitchen of Birkenbridge was the site of a 'science experiment' with substances under high heat conducted by Lord Sutton and the soldiers, including Mr Graham and Mr Hammond. In its aftermath, the soldiers helped the maids clean up, and wrote letters of apology to the cook.