Hello Tim, thanks.
Yes it does prevent new attempts from being opened/recorded. In my case, the final score remains changeable and no matter what setting I use, it is always the latest score that appears. I have solved it on the university moodle by NOT using the popup option and manipulating the moodle blocks to disappear while the Lectora title is running. The outcome is now exactly as I had hoped for, but it took a lot of work to discover the nature of the problem (pity they did not make it public more obviously). The bug appears to have been fixed in later version s of moodle (e.g. my private system).
Thanks again for all of your help.