THE CACHE IS NOT AT THE LISTED COORDINATES
This is the bonus cache for GC753DW Destinations: Night Flight.
The terrain rating is really only about T1.5-2 but as you may well be finding it at night after extracting the numbers from the parent cache, I have added half a point to the rating to reflect the darkness.
To find it you simply need to collect the numbers A-F from some of the stages of GC753DW.
The final location is then: N 51 44.ABC E 000 25.DEF and these are the coordinates you should use in the checker
In fact the actual location has been moved a few metres south and you will get more accurate coordinates if you subtract 5 from ABC and 2 from DEF. Look out for barbed wire and thorns.
Please take care to replace the container so that some of the reflective patches are visible.
Happy caching!