Hampton Library is in the Serpentine Green shopping centre. It's just an interim library, set up in part of the Hampton Health Centre, until the multi-use centre for the township is built.
The coordinates above will take you to the front door of the shopping centre. Go in and bear left until you reach the food court area. Take a seat outside the front of the library / health centre and look for the following information:
### Cache location changed in November 2011 and details below adjusted accordingly! ###
P = The number of capital Hs on the large, high-up, white sign over the library's door. (Have you spotted all of them ? Count carefully!)
Q = The number of lower-case hs on this sign.
S = Look at the orange pillars around the food court. How many lights are there hanging between any neighbouring pillars ? (Unless there are any broken/missing ones !)
T = Look back along the shopping mall. How many arrows are there on the blue/orange directional sign ?
Work out X = S + T - Q
The cache is at N 52° 32. PXS W 000° 15.PX0
Go out of the shopping centre the same way that you came in and follow your GPS ! On arrival, please be stealthy!
(The whole cache trail is wheelchair accessible, although it includes a bit of a slope. To retrieve the cache, you might need help to take the box from its hiding place.)