NORTH + EAST = CACHE
Each letter represents a different numeral from 0 to 9.
Neither N, E nor C is 0
The Cache can be found at
N 51 X
E 000 Y
where X and Y are 4 or 5 digit numbers given by,
X = HC * REE
Y = HH * TO
for example if X = 23,456, than the Northing would be N 51 23.456
I'm not sure if the solution I have used is unique. I've been informed there are 6. You'll have to find the one I used. Please let me know if you find alternative solutions.