OPIE of illogan - 1881 census look up please

[deesam56]

I am still putting my family tree together and cannot find my possible ancestors on 1881 census though they are on all others
I am looking for Thomas and Harriet Opie born 1842/1845 in wendron and kea
they had 2 daughters, Mary Ann b 1874 and Margaretta (retta) born 1878
cannot find them on 1881 census as need that one to confirm something about mary ann
looked at emigrations also with no luck

anyone who can look up please
i have now put this on a different forum