I have a very large collection of Murray references for Sutherland and have had a look for your Margaret. The only possible person would appear to be Margaret Murray, born 3 February 1798 in Dornoch to Thomas Murray and Christian Munro. Margaret had a twin sister Elspet. You will also notice that her mother's name was Christian after whom she named her child. Elspet Murray died in Dornoch, a spinster, on 4 March 1873. Margaret died in 1850. Thomas and Christian had another set of twins: Hugh and William, born 6 March 1801 plus a son James, born 13 December 1791 and a daughter Catherine, born 5 May 1803. All these children were born at Embo, Dornoch.
Hope this helps.
Christine