Nic,

Well spotted regarding workhouses and VD. The girl in question born 1849 was in the workhouse off and on in 1868, 69 and 70 usually "sick" and discharged at own request.
In November 1868 she was discharged from the workhouse to the Lock Hospital "venereal". I don't have a discharge note from there but she enters the workhouse again in 1869 "sick" and again in June 1870.

The 1871 census shows her living with her married sister's family but I can find no further information after that.

Her half brother my great grandfather also a tripe dresser was her cousin and by co-incidence died as a result of VD.

Re the map from 1804 you can quite easily see Rosemary Lane. The Rag Fair was held around the area at the west end where the Royal Mint once stood.