The CDs can be used by more than one person on one computer.
If you have more than one computer and a large number of pupils you either need to purchase a CD for each computer or negotiate a user licence with elevenplusexams.co.uk.
Thanks, just read the overview and it says that tutors need to contact "The Tutors" for a multi user licence. I'll have to find out how much that is to work out whether or not it is financially viable. I only have a handful of pupils!