Kym - there are 2 John Badenoch baptisms on familysearch and scotlands people - one 9/4/1752 son of Alexander Badenoch and Isabel Jamieson, the other 19/9/1755 son of John Badenoch and Margaret Thomson - both at Rathven, Banffshire. Most of the online trees have plumped for the 1752 baptism (perhaps because 2 of John/Isabel's children had the names Isobel and Alexander. Aside from this names angle, I've no idea how you'd decide which of the 2 baptisms is 'yours'.
I think this must be Isabel's baptism, bearing in mind the name of her father:
Isabel Muir b.15/5/1760, bp.17/5/1760 Cullen, Banffshire, dau. of Ebenezer Muir and Jean Barlow.
By the way, John Badenoch and Isabel Muir married 1/9/1787 Cullen (not 1797) - children Ebenezer 1789 Fordyce, and the rest at Cullen: Isobel 1790, James 1792, John 1797, Alexander 1799 and Ann 1805.
Annette