1. Tracked the feature.
2. On the first frame, do your cloning. Make sure the clone settings are set to Constant duration rather than just a single frame. You will need to think about where to choose your clone point so that it will be consistent throughout the shot and won't reveal the stuff you're trying to hide (if you don't get what I mean, it will make sense once you try it! It may work, or may require tweaking, but that's ok too).
3. Add an expression to the Position of the clone stroke (in the timeline, it will look something like Effects > Paint > Clone 1 > Transform : Clone 1 > Position. You need to pickwhip this to the Motion Tracker track point's Feature Center.
thats all good - now I just need to assign the track to clones source point....