The dates are correct Sinann. Relative went to India 1850. The letter was written by a descendant of hers in 1947 to family in England.
The person I am trying to trace is Theresa

who married John O'Connor. Their son, Charles Edward was about six months old when they went to live in India. John O'Connor was a civil engineer and Theresa was a lady doctor.
Thanks for the link - I will see what I can find.