Hi - after a lot of tweaking and help/advice from forum members I've managed to get this 99% the way I want. There is one slight bug which is causing the object to 'pop' or move. If you scrub the timeline between 48-58 frames you'll see the movement I'm talking about.
Does anyone have any idea what could be causing this or how to remove this movement ?
in the SplineWrap (AsplineWrap) go to Object/Spline (the Spline controls at the bottom, not the Spline name slot at the top) make sure Fix Bounding Box is checked. The spline wrap tries to keep objects centered on the spline and your object is changing shape all the time so it moves it (at 48-58 it's really sharp but it moves slowly back from 70 - 90 as the U closes up) Fix Bounding Box is the cure.