The cache is NOT at the given co-ordinates. You must solve the puzzle below to obtain the correct coordinates.
To obtain A,B,C,D and E you need to have completed the Queen Elizabeth Adventure Lab nearby.
S29 (A-2)(A-1).E(C-1)(B+7) E30 BC.ECC
The granddaughter drew a picture. There might be a hint in there somewhere.......
Good Luck!!!