Mickhippy, when your riding over the rough terrain, do you feel the forward to back motion in your upper body? without your back against back rest. Or are you only feeling up and down movement over the ruts?
With the idea of removing the springs from the deck, I have thought of this and would like to try it if its not a big job to remove them, I havnt had a good look at it but is it a matter of just removing the tensioner nuts and then sliding the springs off? I will have a look tomorrow at that.