I thought I would look at Mary Hannah from a different angle
1911
https://www.familysearch.org/ark:/61903/1:1:X7PR-CHFMary Hannah Hearn 46 Bilsdale
Esther Hearn Dtr 21 Middlesbro (Esther Pettit Mar Q 1890 mmn Garbutt)
William Hearn Son 19 Middlesbro (William Pettit Sep qtr 1891 mmn Garbutt
Annie Hearn Dtr 16 Middlesbro (Annie Pettit Sep qtr 1894 mmn Garbutt)
Mary Hearn Dtr 11 Wallsend, Northumberland
Robert Wilkinson Hearn Son 4 Wallsend, Northumberland
Mary Garbutt Mother Female 66 Bilsdale, Yorkshire
........
1901 Wallsend
https://www.familysearch.org/ark:/61903/1:1:XSMY-NW3Robert W Hearn 38 bn Newcastle On Tyne
Mary H Hearn 36 bn Bilsdale, Yorkshire
Edith Pettit Step Dtr 11 bn Middlesboro . (probably Esther Pettit)
William Pettit Step Son 9 bn Middlesboro
Mary E Hearn Dtr 1 bn Wallsend
also 1901 (Middlesbrough)
Mary Garbutt 56 born Bilsdale
John Garbutt Son 34 bn Middlesbrough, Yorkshire
John Perry -Boarder 22 bn Middlesbrough
James A Petitt Boarder Single 21 bn Middlesbrough
Annie Pettit - Visitor 6 bn Middlesbrough
....
In 1891 Mary Garbutt is lodging a few doors away from Mary H Pettit
RG12/ 4008 f110 p15
Mary Garbutt age 46 bn Bilsdale - Widow occ Charwoman
I suspect that her mother Mary was not Widowed but just a cover for the fact that she was still single.
More to investigate but have to stop for now