The Roy- Dalziel family seem to be interrelated. i think it might be worth you doing a bit of sifting through this list. I would think that there is a good chance that that John Roy and Agnes Dickson could be Margaret Roy's parents (and William Dalziel's grandparents.)
John Roy - 15 Dec 1817, aged 62.
Wife - Agnes Dickson - 9 Nov 1843, aged 88.
Children
William - 22 Aug 1785, aged 2
Grizel - 8 Mar 1794, aged 10 mths
Cath - 15 Sept 1794, aged 8
Hugh -21 April 1816, aged 23
Then -
Agnes Dazell - 16 Feb 1839, aged 24. Husband Thos McClure
Jas Dazell (as previous message) and wife Margt Roy (as previous message)
Jas Daziel wife Mary Hudson - 27 March 1904, aged 74
Thos Dalziel - 29 April 1899, aged 80. Wife - Isabella Robison 25 jan 1900, aged 81 and-
imo da Mary G d. 16 Feb 1857, aged 5, s. John d. 1 March 1858, aged 11, s. jas, 4 April 1869, aged 20, s. Thos G 23 Feb 1888, aged 21, s. Wm 27 March 1892, aged 36, da Agnes Helen 16 March 1895, aged 34
William Dalziel 16 Jan 1915, aged 80
Gadget