Mary Ann White's mother was Elizabeth Groves, Mary Annie's sister.
The house at 25 Westow St occupied by the Jenkins in 1891 housed the family of a Scottish Builder & Decorator John Stewart, in 1901.
So Mary Annie could be the Mary Ann Jenkins in the St Pancras workhouse? infirmary in 1901, and who died there on 1st Jan 1902.
I think I will go for the Death Cert.