Yeah it's not to do with speed bumps as such or the jerky spaz clutch action that beginners/learners have.
I was thinking it may be something to do with my seat position also, like it's giving my leg/foot too much freedom (or something) to move back/fwd or up/down involuntarily?
What I am basically saying is...hit bump and G's force foot on throttle, car accelerates...acceleration moves weight back and foot lifts off throttle a bit, car then decelerates, weight moves forward and foot is forced on throttle...car accelerates moves weight back and foot lifts off and process repeats.
Like I said it's in 1st and 2nd mostly. If I'm in 3rd then there seems to be more a dampening effect, as the car doesn't accelerate or decelerate so much with the same throttle inputs.