*The reference coordinates are not to be used as the cache is NOT hidden there*

When left to right is divided by the Magic Number the remainder is .90909091

When right to left is divided by the Magic Number the remainder is .90909091

The difference between the digits when read from right to left against reading them left to right is divisible by the Magic Number WITHOUT any remainder.

The Magic number consists of two identical digits and it also has a big part to play in working out the coordinates. Take one of the digits of the Magic number and insert it to the left, or to the right, or in the centre of the Magic Number to reveal West. Double West for North.  

The coordinates are to be inserted like this:-

N53°53.???
W 009°38.???