Hi Keith
I visited Layston church yesterday,I had a good look at most of the headstones,unfortunatly I could not find your Grandfathers.
There are a lot of stones that are un-readable now, and a few that have no headstones.I will look again for you when I go just to make sure.
Have you tried the dioscese for Buntingford as they will have a map of all the graves,names dates etc.
Dave