In Duffus parish, Morayshire in the 1881 census there is a Robert Campbell Snr aged 58 listed as a baker (employing 3 men) living with his wife Ann. This would seem to be the parents of Robert John. Robert Snr was born in Dornoch, Sutherland.
Of the listed children, Robert (Jnr) is the eldest at 19 and is also listed as a baker.
The other children listed are Jessie (14), Jean Ann (9), John (6), Thomas (4).
They have two boarders listed as bakers - must be the other two employees of Robert Snr, and a young girl living there listed as a servant.
In the next census (1891) Robert Jnr is no longer living with his parents so this would seem to tie up with him getting married in Belfast four years later.
Does any of this tie in with any other facts you know?