Hi Maggie, welcome to RootsChat

You don't give any dates in your quest which is important.
How accurate is your info?
Do you have the BC of your grandparent, the child descended from James Leask & Mary Weir?
I can't find a marriage for James Leask / Mary Weir.
Does the BC of your grandparent state Mary Leask, Maiden Surname Weir or simply Mary Weir?
The BC of your grandparent should give a date & place of marriage if they were indeed married?
What's the name, date & place of birth of your g/parent descended from James Leask & Mary Weir?
Annie