Cache is located at S 33 2A. BC3 .E 149 3D.EF3
The following audio link has the answers for the missing co ordinates
https://2mce.org/podcast/mary-ann-roberts-mystery-woman/
A= Mary Ann Roberts husband is Richard ? Number of letters in surname.
B= First house built 18B6.
C= Louisa born in 181C. Take 2 from answer
D= Mary Ann had 1D children. Add 3 to answer
E= First husband died 182E. Take 1 from answer
F= Number of children in Mary Ann Roberts second marriage. Take 2 from answer