hampan:
Knockagarran townland is in Convoy civil parish which is just to the west of Raphoe civil parish. I assume your Mayes ancestors were Church of Ireland? Unfortunately, there are no church records back to 1710. The Raphoe C of I records go back to 1771.
I also checked the 1858 Griffiths Valuation head of household records and there were no Mayes records anywhere in Donegal. I also did not find any Tithe records with that surname in Donegal.
Roger McDonnell