Most certainly Mrs Mary McCarthy of 1 Breezer's Hill, Pennington Street, St George's in the East. Born c.1861 in Shoreditch, married to dock labourer John McCarthy (b. Whitechapel c.1855). In 1891 they are recorded as having three 'unfortunates' (prostitutes) lodging with them.
Following claims made by Elizabeth Phoenix (her sister-in-law), Mrs McCarthy was traced by the press. She told reporters that Mary Jane Kelly had lodged with her after a brief period staying with another woman, Mrs Buki, in St George's Street (Ratcliffe Highway) after leaving the West End. Mrs Buki apparently accompanied Kelly to a French 'lady's' residence to reclaim some of her property. This statement appears to support stories that Kelly worked in a high-class brothel (or 'gay house') in the West End.
Mrs McCarthy also said that in late 1886, Kelly left Breezer's Hill to live with a man who was in the building trade (possibly Joseph Flemming). She also believed that Kelly would have married this man, however, she stated that a while after, Kelly knocked at her door at 2.00am one morning to ask for a bed, saying that she was no longer with him.
There is no evidence to suggest that the McCarthy's of Breezer's Hill were connected in any way with John McCarthy of Dorset Street.