In 1891 Ann is a widow, still at 47 Union St., Mansfield. With her are children Alfred 22, Arthur 20, & Ellen 16. Also in the household is William Slack, 21, a lodger. Is this her son William?
She is probably the Ann Slack, age 64, living with Arthur & Eliza Slack in the 1901 census. She is identified as Arthur's mother.