In addition to finding Roscommon Stanley members in Birmingham (https://www.roscommonstanley.me.uk/possible-relations/from-roscommon-to-birmingham/), I also discovered one in Liverpool.
The 1851 census shows John Stanley (yet another one!) in Allerton, West Derby. John was born in 1813 (but 1815 on later census returns). His occupation was garden labourer. He married Jane Griffiths on 15 February 1843 in the Parish Church. John’s father was Michael, a labourer.
The eldest child, Mary, was born in 1844. Other children include Elizabeth, Ann, John (inevitably), James and Ellen (born 1859).
By 1871 the family’s address was Allerton Hall. Both John and son James were Gardeners/Domestic Servants. The Hall is now known as the Pub in the Park. Its past glories are somewhat diminished. It is clear that a substantial staff would have been required to keep the grounds in good condition.
The fact that John was in Liverpool in 1843 means that he wasn’t driven to emigrate by the famine. His father Michael must have been born in the 1780s or 1790s. I know no more about them. As with the Birmingham family, the only possible connection to me is the surname allied to the place of origin.