Knighton

Knighton 28.5.1803 / 3.3.1809 Dr Knighton at Joseph Johnson's / 2.2.1810 again / 14.12.1810 Knighton at Johnson's / 12.3.1827 Knighton adv at Northcote's / 3.6.1827 Lady Knighton & fils at Northcote's / 10.6.1827 letter to Knighton / 11.6.1827 write to Knighton / 5.7.1827 again / 1.8.1827 call on Knighton & secretary of state / 3.8.1827 call on Knighton / 26.10.1830 call on Nortcote adv Knighton
Very likely  William Knighton DNB 1776-1836 courtier and physician, moved to London 1803, made a baronet 1812 and became advisor to George IV (which fits Godwin's writing to him) and had "taste, especially in painting, being a friend of Lawrence and a patron of  Wilkie" (DNB) which fits his visits to Northcote. His wife was Dorothea nee Hawker and his son was William Wellesley Knighton 1811 - 1885