There is further evidence that he did exist and continued to live in London.
He was said to be of St Martins in the Fields parish when he married Elizabeth Allen at St Stephens, Coleman Street on 30th October 1698. The name in the register is Lancellot Keate.
KEATT, Launcelot (Grimwade p.567)
Moderators: buckler, MCB, silverly
Re: KEATT, Launcelot (Grimwade p.567)
1714 Launcelot Keate in the list of freeholders found in the Poll book for Strutton Westminster. 1714 is the year of publication.
5 April 1718 Lancelot Keate of Saint Martins in the Fields Goldsmith paid apprentice indenture duty for Richard son of Richard Bowles of Branstone Lincolnshire Gentleman.
11 April 1730 William Whitaker of London Gentleman paid apprentice indenture duty for Lancelot son of Lancelot Keate of Westminster Goldsmith.
5 April 1718 Lancelot Keate of Saint Martins in the Fields Goldsmith paid apprentice indenture duty for Richard son of Richard Bowles of Branstone Lincolnshire Gentleman.
11 April 1730 William Whitaker of London Gentleman paid apprentice indenture duty for Lancelot son of Lancelot Keate of Westminster Goldsmith.