 Mectalfe is said to have been the apprentice of Robert Jones (died in 1774), a wine merchant and East India Company director who became a member of Parliament for Huntingdon from 1754 to 1774.According to English painter and diarist Joseph Farington, Jones wanted Meltcalfe to marry Ann Jones (1747–1832), his only daughter and sole heir, she was still a minor when she chose instead to marry with a Marriage license a British officer, James Whorwood Adeane (1740-1802) at Marylebone on 5 March 1763.Through his brother Christopher, Metcalfe became involved with the Three Mills venture in 1759.