Thanks Craig, I think that is similar the workaround I've come up with. I've added an additional completion criteria stating they have to achieve a minimum of 115 (grade is made up of the minimum pass score of 15 for the quiz and 100 for the assessment interview). I've tested it and it appears to be working and showing learner who achieve less than 115 as partially complete overall even though they have taken part in all the activities.
Unfortunately we are some way off upgrading to version 12 but nice to know that it has been dealt with in that upgrade.
Sue