Set for the 2018 Winter Geolympix Mega with help and permission from the National Trust. If you intend to take part in the Letter/Box Challenge (Find 36+ LetterBox/Hybrid caches: A-Z, 1-10 and others, on the day of the Mega) or would like to see this cache in 'fancy' mode on the day/night of the Mega you may wish to leave it for now.
A Puzzle-type Letterbox/Hybrid cache (please don't remove the ink pad or stamp; they're not swaps) - The cache is NOT at the given co-ords. You have to crack a puzzle or code first. The cache is within a mile or 1.5Km of the given co-ords.
Method 1: Use some AANDs (Aluminium Alpha-Numeric Discs. There are around 4,000 in circulation) and go to N51° 48.CCH' W000° 35.GFJ. Ohbjhmf vghbg bnlahmzshnm ne ZZMCr xnt mddc bntkc ab x 1/100 drbpp, pl F'sb xaaba pljb zirbp ql qefp mxdb.
Method 2: Solve this cache's twin, and deduct 0.053 from the Northings and deduct 0.189 from the Westings to get the co-ords for this cache. Easy! This also works vice-versa, of course...
Method 3: Take the final digit of the year these videos/promotional films made their public debut to calculate the final co-ords of this cache, using the following formula. There are larger versions in this cache's Gallery if you need a better look. Good luck!
The final is hidden at N51 4A.BC W000 3D.EF where:
A = L+M
B = Jx((H+T)-R)
C = (N-K)+(Z-V)
D = (U-G)+(P-Q)
E = ((W+O)xY)-M
F = X-S
Checksums:
G+H+J+K+L+M+N+O+P=45
Q+R+S+T+U+V+W+X+Y+Z=46
G = 
H = 
J =
(No I to avoid confusion with 1)
K = 
L = 
M = 
N = 
O = 
P = 
Q = 
R= 
S = 
T = 
U = 
V = 
W = 
X = 
Y = 
Z = 
Please DO NOT remove the stamp or ink pad. Neither is a swap - They make this cache a LetterBox/Hybrid. Thank you!