Charles Coltson Born 1720s Died 1790

Charles Coltson married Ann Field in 1747 in the City of London. His family may have been quite well-to-do, as Charles worked at Chatsworth House in Derbyshire. In his Will, dated 1785, he is said to be living with the Earl of Bessborough. Whether he is connected with Coulsons or Colstons I do not know. Charles and Ann's children, Charles and Charlotte, were baptised in London in 1749 and 1750. What I am searching for is any information about when Charles snr was born, who his parents were, etc. Any information most welcome.