Good morning Foz
This is a summary of my findings - easier than following above in some ways:
I could not find the birth of a John Hairstens and variations, so I checked out his marriage cert. Here, it states that his parents were Thomas Harstens (gardener) and Mary Hairstens nee Clark - He gives his age as 23.
I then went to check on their marriage and only found one - Thomas Hairsteens, m Mary Clark in Troqueer, Kirkcudbright. Thomas was a widower. Mary was a housholder and Beekeeper, spinster.
No John Hairstens/variations around this time so checked a John Clark. Found a birth of John Clark on 29 April 1858, Troqueer. 39 Church Street, Maxwelltown, illegitimate. Mother Mary Clark, father (now we know) Joseph Nichol or Nichole, resident of Dumfrieshire.
Check the 1861 census for confirmation of this and find Thomas Hairsteens, gardener, aged 43, born Sanquar, Mary Hairsteens, 32, born Troqueer, and John Hairsteens, son, aged 3, born Troqueer, living at 39 Church Street, Maxwelltown.
Checked for a Joseph Nichol, found one in 1861, aged 19, tailor (ap) , living at 6 Academy St, New Church, Dumfries, aged 19, nephew of Thomas Nichol, shoemaker. All born Dumfries
Mary Clarks parents, from marriage cert - John Clark, labourer, deceased and Jane Clark, nee ? Summer
something (might have to put up for reading), deceased
Thomas Hairsteens parents, from marriage cert - John Hairsteens, farmer, deceased and Margaret Hairsteens, nee ? Pedine
So the answer to your question is: birthdate - 29th November 1858, Troqueer, Kirkcudbright. His parents - Mother is Mary Clark; social father - Thomas Hairsteens; biological father is Joseph Nichol.
I'll go and have a look at your McGowan thread now.
Gadget