Thanks for the feedback.
Is is recording results as a standard user (not logged in)? Will check it on my dev install at some point tomorrow to see if I get the same issue.
Great suggestion to export results. Will look at doing a basic CSV in the future.
Regards to multiple responses, not had that in mind when developing the plugin but may look at it for the future. For the time being, it might be an idea to check out our sister plugin WP Survey and Quiz Tool (http://wordpress.org/extend/plugins/wp-survey-and-quiz-tool/) to see might be a better option.
I'll try and get back as soon as I can about the issue though :)