Where did the Greig family live? From the census links provided by Neale1961 in reply#1 the abodes were:
1841 Relivourkie
1851 Greenan
1861 Relivourkie
1871 Meadowcape
(all on the Isle of Bute)
In newspapers there are only two references to Relivourkie, both from 1790, concerning the sale of several lots of land. In this snippet you can see the reference to Relivourkie as part of Lot I, and note, at the bottom of the snippet, the reference to Lot II as the Mill of Greenan.
24 April 1790: Caledonian Mercury