To find the cache you need to visit all the waypoints and find the required information, the cache is at: S36 5A.BCD E174 2E.FGH:
A = The Mess
How many heads are in the bottom left photo?
B = WAAF Toilet Block
How many coppers for heating water?
C = The Pump Shed
4th number of the year on the last line
D = Cosmic Noise Expedition
Last digit of the year that the supernova Crab Nebula exploded
E = A First for Piha
2nd digit plus the 4th digit of number plate
F = Two Towers
2nd digit of distance of Log Race Road
G = The Radio House
Number of letters in the 2nd name of the company that made the transmitter
H = Piha Radio Station Stories
The number for 'Window on the Universe'