In late 1828 or early 1829, Fairfax returned to Britain on leave of absence, leaving St Helena under the command of her first officer, Mr. Benjamin L. Harrison [REF].
Before St Helena left, Harrison agreed to carry a letter to Sierra Leone which represented a deviation from the most direct route back to Britain, at the request of Commodore Francis Augustus Collier, the commander of the anti-slavery West Africa Squadron, on the frigate HMS Sybille.