This cache is hidden at the published co-ordindates, but as it is a Challenge Cache, you have to meet the below criteria before you can log a find and claim the smiley
Qualifying requirement: To have found 650 caches or more caches with the 'Dogs' attribute. Please use the example log that the challenge checker generates, you can of course add more to it 
We qualify for this as we have found 656 at the time of creating this challenge. We have decided to place this cache and challenge as we enjoy walking Mr NSCR's Dads dog, Maizy (see below)
The D rating is a reference to the amount of caches that you have to find to complete the challenge and the terrain is for the hide itself
You can check whether you qualify for this challenge using the following Challenge Checker at Project GC. Under the Dog.....
The cache has been placed with the permission of the Dartmoor National Park and complies with their geocaching guidelines.