Hi Jo,

Rather than assign a permission to the role, what you can do is edit the report, go into the Access tab and choose the new viewer role as one that has permission to see that particular report. You'll likely need to change the 'Content' dropdown to 'Users may have role in any context'. This video from the Reports course should help: https://youtu.be/Q7NjjOr5Y1I?t=4m37s

Thanks!