I was so excited when I first stumbled across a Geocache where one needed to solve an on-line Jigsaw (GC6ZD2B Last one!) as it combined two of my favourite things. Many, many jigsaws later and I am rather less excited, although I have developed a bit of a shape-based solving technique that I now use in physical jigsaws. Indeed, when somebody posts a 300 piecer with nothing but leaves it makes me 'see red'. I'm not sure this one will be much of an antidote, although it's only 120 pieces.
The Geocache is not at the posted coordinates: that is a dangerous section of the A40 and you must not stop there. Certitude will help once you have worked out the coordinates.
You can validate your puzzle solution with certitude.