A classic Reverse Wherigo for Sark.
Begin by downloading the Reverse Wherigo cartridge (or ensure your previously downloaded version is up-to-date).
Then go to the given co-ords - one of Sark's less-visited corners - and find a heavy metal object. The numbers on it AB-C-DE, the number of arrows on the top, close together is F, and the lone number close to the crest is G.
Enter the numbers gathered into the Reverse Wherigo cartridge in the following format: three rows of six numbers, without gaps:
(A+B) E (F+D) (A+C) F (B+E)
(G-C) (E+G) (A+D+F) (AxD) (F-D) (B+E)
A E (F-D) ((B+G)-F) (C+C) ((A+E)-G)
This will activate the 'Reverse Wherigo Box' in the app, which will - at the press of a button - tell you how far it is to the cache BUT NOT THE DIRECTION! Thus it's up to you to zero in on the container which is nowhere private or dangerous. Nor in the sea...
Good luck & happy hunting!
My other Channel Islands caches:
Alderney: Dear Lyn E (Alderney, CI).
Alderney: It's the Fort that Counts - Alderney.
Alderney: Count the Bright Hours Only... (Alderney, CI).
Alderney: Going Ballistic on Alderney.
Jersey (well, south of): Capt'n Simply's Pirate Booty.
Guernsey: Bridging the Divide (St Sampson/Vale, Guernsey).
Sark: Kars (Sark, CI)
Sark: Hunting on the Sark - Here!
Sark: Rings a Bell
Sark: Peake to Peak.
Herm: Smirfe Hole (Isle of Herm, CI).