Ages in the 1841 census are well known for inconsistency and the 1841 ages look a bit suspect to me because in 1851 Mary wife of William is in Gt Ancoats St with Benjamin 21 and Henry 19 but no sign of William Snr. Looks like William Jnr is a lodger in what looks like Buller St St Jude. This Mary was born in Hunslet that squares with the Not Lancs in 1841 and the 1861 where William is present as a Waste Dealer. He appears again as 2 years younger than Mary.