William Mortimer Farmer bought Seaforth from William Brading in the 1870s and demolished the old dwelling-house and cottage and built a home, retaining the name Seaforth. Farmer owned many properties in St James.

He was born in Wynberg on 3 December 1836.

He was heir to the Maynard fortune and rose to prominence in the 1870s when he, among others, made a notable contribution to the economic upliftment of Wynberg. He was a successful businessman and was a partner in W. G. Anderson & Co., the shipping agents for the Union-Castle Line. He was also a Member of the Cape Legislative Assembly serving the Wynberg Constituency from 1879 to 1883.

He died in England in 1899 and his deceased estate was liquidated in 1900.