The cache is not at the start coordinates. You must travel to the Waypoint. Note that there is no need to trespass on railways, schools or substations to solve this cache!
Once there you will need to find the phone number 08000 ABCDEF
The final cache is located at N 51 28.A,B+C,B+D+F W 000 30.E,C-D-F, D+F+1