This is a webcam cache, therefore no physical container exists.
Go to the posted coordinates, which is beside the water along the South West Coast Path and load the following web page to view the webcam:
Take a screenshot of you at GZ, stood where the arrow is (as per the image below), and post it with your log, that's it. Should you not have adequate phone signal at GZ you could always PAF. Photos will only be accepted from the webcam and not from your phone.