Hello Molly,
     Found a transcription of the 1871 Census but the original must be difficult to read. No surname for Ann's son-in-law and family.
       1871 Census. 176 South St, Perth.
     George    --  30  Shoemaker.   
     Jane       --  34     
     Helen      --    9      
     Mary Ann --    5
     Jane        --    3
     Jessie      --    2 All born Perth.
     Ann Nicol  77  Mother-in-Law b Schberman? Perthshire.
     ScotlandsPeople has a death for an Ann Nicol, other name McDonald, age 85, 1879 at Perth.
     Not what you were oiginally looking for, but a good find if it's the right person.
               Regards,     Dod.