Early 18th century.
The blue plaque says:
The Prebendal Houses of Southwell.
Southwell Minster was founded as a Collegiate Church and was served by canons whose incomes came from the revenues of local parishes called prebends. The canons formed the Minster's governing body, called the Chapter.
Each canon had his own house around the Minster. Members of J.T.Becher's family lived at Oxton I Prebend, since re-named Cranfield House, and at South Muskham Prebend.