The Multi
~ At the waypoint for Stage 1, take the three numbers after DP, and call these A, B and C.
~ At the waypoint for Stage 2, take the three letters that have been punched out, and call these P, Q and R. Convert to numbers using A=1, Z=26, etc.
The cache can be found a short walk away at:
N51° 30. (C + 1) (A) (B / 3)
W001° 11. (P x 2) (Q - P) (R - 1)