Here’s some links that you may find useful.
Transition Chichester www.transitionchichester.org
Chichester Harbour Conservancy www.conservancy.co.uk
Friends of Chichester Harbour www.friendsch.org
Murray Downland Trust www.murraydownlandtrust.org.uk
Sussex Wildlife Trust www.sussexwt.org.uk
Manhood Wildlife and Heritage Group www.mwhg.org.uk