Suffolk County Councils Countryside Service would be the best place to start. their contact details are:
Suffolk County Council Headquarters
Endeavour House
8 Russell Road
Ipswich
Suffolk
IP1 2BX
Switchboard: 01473 583000
If their not aware of geocaching a useful document explaining geocaching can be found
Here. you might get passed from one person to another at first, but hang in there and you'll reach the right person in the end.
Dave
My post is my personal opinion and as such you do not have my permission to quote me outside of these forums!
Dave
Brenin Tegeingl
Formerly known as Mancunian Pyrocacher on GC