- Born: 1 Apr 1807, Islington, , Middlesex, England
- Christened: 17 Apr 1807, St Mary, Islington, Middlesex, England
His birth & baptism record is on the same page as his brother James.
In the 1851 Census there is a record of a William Anstiss aged 43 (ie born abt 1808) and unmarried residing at 23 Princes Gate in Knightsbridge where he was a Butler. He was born in Islington. Given this and the date this is probably he. the Head of the household was The Honourable Louisa Emily Baring, 70, an Annuitant. Her sister The Honourable Emily Louisa Baring, 60, an Annuitant was also living there. Apart from William there were 8 other servants in this household including a Housekeeper, Ladiesmaid x 2, Kitchen Maid, Scullery maid, Housemaid, Butler, Under Butler and Footman!