Hi Helen,
Just so you have all the information. I chased the Robert/Mary couple through the census and George too.
1871 - Wolflee Lodge, Southdean, Roxburghshire
Robert Minto Head M 52yrs Gamekeeper b. Jedburgh, Rox
Mary Minto Wife M 47yrs b. Southdean, Rox
Euphemia Minto Dau 15yrs Pupil Teacher b. Southdean, Rox
Ellen H Minto Dau 12yrs Scholar b. Southdean, Rox
Mary L E Minto Dau 9yrs Scholar b. Southdean, Rox
Jessie H Minto Dau 6yrs Scholar b. Southdean, Rox
1871 - 2 Brougham Place, Hawick, Roxburghshire
Mary Ann Oliver & children
George Minto Lodger 18yrs S Commercial Clerk b. England
(I could not find any other George's to fit in England or Scotland)
1881 - Wolflee Lodge, Southdean, Roxburghshire
Robert Minto Head M 63yrs Gamekeeper b. Jedburgh, Rox
Mary Minto Wife M 58yrs Gamekeeper's wife b. Southdean, Rox
Mary Minto Dau S 19yrs Nurse (Domestic Servant) Unemployed b. Southdean, Rox
Jessie Minto Dau S 16yrs General Domestic Servant b. Southdean, Rox
1881 - 3 Minto Place, Hawick, Roxburghshire
George Minto Head M 28yrs Painter's clerk b. England
Lillias Minto Wife M 28yrs b. Kirkaldy, Fife
1891 - Wolflee Lodge, Southdean, Roxburghshire
Robert Minto Head W 73yrs Gamekeeper b. Jedburgh, Rox
Mary Lena Elder GDau 12yrs Scholar b. England
So that fits in with the info that Ricky found for you regards the 1891 census. So to me it looks like George Minto who married Lillias (McKinlay) (I assume this is the marriage you have) is indeed the son of Robert Minto and Mary Telfer. Of course nothing is certain and maybe Mary had a fling with a George Minto before marrying Robert...who knows
The birth cert will help out a great deal. Also could not find George and Lillias in 1901, do you know what happened to them? Or where they may be?
Jenny