The published co-ordinates are not for the location of the cache, but may be a good place to start or at least, very close to a good place to start. Instead, if this ...
... was from A to B, then the cache can be found at the following coordinates ...
N 51 20 . A – ((A-B) x (A-B)) + 27
W 000 44 . B – ((A-B) x (A–B)) + 181
Please don't leave any additional clues (subtle or otherwise) in your log.
And please could you bring something to write with, as there is no pen/pencil in the cache.
You can check your answers for this puzzle on Geochecker.com.