You are looking for a camouflaged bison tube.
Cache is not at the above coordinates but you will need to visit the location to gain the numbers needed.
On the post box, there is a post box number CFABCDE
Final location can be found a short walk away at N51 28. AE (B-C) W03 28. (D+B) (A+C) (D-A)
The Fine Pair series was originally started by wizardsmum but is now managed by mattd2k.
If anybody would like to place 'A Fine Pair' of their own please do. I would just ask that you first visit www.afinepair.co.uk to request a number to avoid any duplication.
mattd2k also keeps a public Bookmark List of this series. Once your cache is published please contact him firstname.lastname@example.org to have yours added.