Riders are free to ride a 200km on the day, either as a return at the halfway point or just one of the legs (ie. Bristol to London or visa versa).
Obviously those riding a 200 or 400 will gain full AUK points (2 or 4 points) plus challenge points towards their respective club as part of the event (although these have nothing to do with AUK and will be suitably policed by myself and Jonah).