I am firmly in the school of if its available use it. So I have a transponder and get (whenever possible) a traffic service. If you don't want to talk to anybody, fine, squawk "listening" and at least the radar controller looking out for me can see you and the Gatwick Controllers won't be on the edge of their seats watching to see what you do next, because using that squawk implies you have an idea what you are up to and where you are.