There does not appear to be any obvious connection between your Purkisses and the Purkises of my cousins. However, in a world in which illiteracy was rife, I do not suppose the omission or addition of an 's' would have caused a hair to be turned! The year of birth of my cousins' William John Purkis could have been as late as 1850 or as early as 1830, so William John Purkiss might be the same as William John Purkis (with one 's'). William John might have been Mary Ann's father or her brother. Mary Ann might have born as late as 1860 butI suspect that it was much earlier for her to be widowed by 1883. Do you have her address at the time of her marriage in 1883? Do you have any idea of the date of her earlier marriage to Mr Bryer? It would be interesting to check the nearest census for her addresses immediately prior to both marriages. In the meanwhile, I shall look for Mary Ann Bryer on the 1881 census.