ATDO are no longer an entity, and APlan have assured me they can cover me on a track day at Goodwood on the 1st May organised by a new track day provider. I did not get the impression that a wording change was needed to still have cover although for piece of mind having the correct wording seems like a good idea in case the underwriter decides to turn tail. As I understand it the ATDO was set up in the days when you could hire a circuit with no marshalls, medical cover, etc however I understand much of that is included by the circuit owners in their hire cost nowadays.