Me again Judy.. and now you can start to get mildy excited.
I've found what I thought my memory could recall..
We have to find out if your JOhn Halliday was born in 1737 to John Halliday and margaret Dinwoody ( Dinwody or Dinwoodie Ive seen various spellings)
IF this is the case then you have a large well researched tree by at least 3 other Halliday researchers.
I made contact with a lady in Canada last year and was able to put her in contact with 2 others from her tree as well as a fellow who lives in Edinburgh and has written an extensive paper on this family. It was 93 pages of hand written info which I have typed up and hopefully the typed copy was passed onto him in Edinburgh.
On the tree that I have in front of me it has JOhn Halliday born in DFS in 1705. He died July 28th 1786. Married Margaret Dinwoody in ??
John was the son of Matthew Halliday born 1676 and Margaret Thorburn. All the family where around H&C so this makes perfect sense with your margaret and John/agnes.
In both the sources of info I have here neither has any further info about John Halliday and Margaret Dinwoody !! so are you the missing link?

?
Somehow we have to find out more about your John and whether he was born in 1737.
Please email on (*)
so I can share further info with you and contacts.
In the mean time I'll do some looking for any evidence that may help with your John. Although it sounds like you may have exhausted all sources?
Also need more info, if you have it, on any other children to your John and Agnes so we can try and look at naming patterns..
JOhn born 1705 had a brother William born 1707 - his side of the family is well documented... just not his brother John's as mentioned before.. hoep that all makes sense
look forward to your further contact.
Anne-Louise Halliday
(*) Moderator Comment: e-mail removed in accordance with RootsChat policy,
to avoid spamming and other abuses.
Please use the Personal Message (PM) system for exchanging personal data.
New members must make at least three postings before being allowed to use the PM facility.
See Help-Page: http://www.rootschat.com/help/pms.php