Symmetry N51 GC1 Mystery Cache

My first contribution to the Symmetry series where the last five digits of the Northing and Easting (or Westing) are the same, this one being in the puzzle style.

Please see Symmetry N51 PA1, the very first cache, for an explanation of this series.

The cache is not at the published coordinates. To find it you need to find four numbers.

Lot of nettles about I'm afraid, but I hid the cache whilst wearing shorts and came out unscathed..

I've put a ready made, camouflaged, micro cache in the container, please feel free to take it and hide it....IF you haven't hidden a cache before.

If anybody would like to expand this series, please do so; I would just ask you to let parmstro know first, so that he can keep track of the names and numbers to avoid duplication.

You can check your answers for this puzzle on Geochecker.com.