This cache is not at the posted coordinates. The posted coordinates are for a sign with information about Lord Rosebery and a map of the park.
The information you need for this puzzle is somewhere on the sign in the format ABCDE FGH IJK. You can assume N51 and W000.
(B)(D+E).(F+B)(C)(B)
(D+D+H).(H)(J)(E)
