This is NOT a puzzle cache, the cache is at the co-ordinates listed.
However, as the walk from the Dog and Doublet pub to Kingsbury Water Park gets very busy, with muggles watching birds, muggles floating by on boats, muggles walking dogs, muggles out with the kids and muggles in general I have had to make the caches up this end of the stroll more difficult to find. They tend to be smaller and more cunning.
Being the nice people us 5Taylors are we thought we might provide you with a hint of what you are searching for. Obviously you are free to go searching without the hint.
The number 12939 is chosen deliberately. To see the hint you will have to write it down on a piece of paper then hold it up to the light. Or you could try a calculator in front of a mirror. Have fun!