Hi Marius and Gordon,
Yes, a one-off solution for this student is possible, but, maybe I'm lazy, I'm looking for a permanent solution for future serious students who are not satisfied with getting things right just once. I'm also looking for one that doesn't clutter up the Moodle page too much because students get confused. One of the things that's so wonderful about QuizPort is that so much clutter from my courses has been removed.
It also seems to have solved the problem of students being ejected from my courses because of server overload which happened with the Hot Potatoes version of WebRhubarb exercises.
Thanks a million for that, Gordon.