Hello Rich....I like the idea behind this image but there are a number of points I would like to make.
I feel the crop is to tight to the left and if you moved around to the right a little you would have picked up the second stone on the thirds to make it stronger.
I would have cropped the sky more to make this image a square format.There is enough mood in the sky for the image not to lose that.
I would also have cloned out the people in the distance...easy to do in PS.
The light and detail in the large stone is spot on so a good moody shot is on the cards at this location.