Send a message to the person who requested a photo of the grave monument of John MacKinlay with the following comment:
I think that Edward Potter may be my wife's great-great grandfather and I should like to know the name of his Mackinlay wife.I don't think I do want to know cousins who must necessarily be very distant ones.I promise I will acknowledge the image and thank you for it. If you would like a financial acknowledgement then perhaps you could suggest a fee.