Although it took a little bit of time to set up the questions and work the conditional formatting of the spreadsheet, I can now use this as a template for all online quizzes.
The actual homework can be found here: http://bit.ly/L6-C2-3
This also gave me the advantage of reinforcing the belief that teachers monitor pupil participation out of lessons and I was able to send brief emails to students the night before homework was due to ensure it was completed (see the difference between completion of the Class 2 students vs Class 1 due to this reminder!)