I have a John Robertson who married a Helen Smith 12th January 1777, Tibbermore Perth Scotland. They had the following children;
Thomas Robertson christ 12th April 1778 Fortiviet Perth Scot
Jean Robertson brn 2nd April 1780
John Robertson brn 6th April 1783
David Robertson 20th March 1785
Nelly Robertson 25th June 1787
Lilias Robertson 6th Sept 1789
Ann Robertson 3rd March 1793
John Robertson 24th May 1795

If any of this information sounds familiar please don't hesitate to make contact. I did note the two John Robertson junior, the only reason I think maybe there could be two was that the first born John may have passed away early in life. Look forward to hearing from you, Shirley.