Hi Jane
I've found the Donald (listed on the 1841 with wife Janet) on the 1851:
Stroniba, Kilmonivaig 99 ED 15 Page 5
Donald Stewart, widr, 65, ag lab, b.Inverness, Laggan
Janet, daughter, unm, 22, houseservant
Mary, granddaughter, 12,
Isabella, d-in-law, mar, 25,
Cl?nny, gdaughter, 7,
Angus, gson, 5,
Donald, gson, 2
All except Donald b. Kilmonivaig.
Regards
Gadget