Jan
I had a look earlier at your previous post (an old one from 2007
www.rootschat.com/forum/index.php/topic,268256.0.html)
It is certainly hard to get a lead on a possible birth for David. I'm curious about what your relative wrote on the back of the 1891 census (D.H.S. 16/6/1884) which as you say, could this possibly be David's birth entry.
The names of David's parents came from his 1923 marriage cert. There is no marriage showing to a set of parents with these names until after 1906 (I didn't filter out on SP where in Scotland). So, given we have a possible entry for him in 1891 with his paternal grandmother Catherine, the question I would have at this stage is whether the name of mother on his marriage cert is correct. Have you double checked on his death cert. what it says about his parents?
From Hume's info on a possible 1891 entry for your David:
Address: Ford, Kilmartin, Argyllshire
Catherine Ferguson, f, head, 68, general labourer, Kilchrenan, Argyllshire
John ", m, son, 40, agricultural labourer, Kilmartin, Argyllshire
Christina ", f, g-dau., 18, general labourer's daughter, Kilmartin, Argyllshire
David ", m, g-son, 7, scholar, Buteshire
Catherine ", f, g-dau., 3, -, Lochgilphead, Argyllshire
And then the possible entry in 1901 for David now showing a birth place in Dunbartonshire. I cannot see a David born in Bute for 1901.
What occupation showed for father Duncan on David's marriage cert? I did see a possible entry for a Duncan, son of John and Catherine, in Luss Dunbartonshire in 1891 but married to an Agnes with children younger that David's age. I'm beginning to wonder whether David's birth may have been illegitimate? If his mother's surname was not Campbell and his birth was registered under her surname (back to that R.H.S entry), it may then explain why everyone has been struggling to find his birth either in Dunbartonshire/Argyll/Bute.
Monica