This final cache in the series is not at the location indicated. To find the correct coordinates you'll need to take note of the letters inside the lids of the caches in the series. Most of the caches have a single letter inscribed, and you must note which cache has which letter.
This will give you numbers to help complete the following:
N 53°13.CAE,W 001°13.RSM.
CAE and RSM are letters from the cache lids. To convert them to numbers, simply use the number of the cache you found them in. For instance, if "C" was in "PCP04" then C=4. Count PCP10 as zero, and ignore PCP11 altogether.