Backup and Restore - include Category Enrolments

Hi all, 

Does anyone know if there is a way to get a course backup mbz file to contain the roles and users of those that were enrolled on the course/had access to the course (because I appreciate that they are not directly enrolled). 

I have created an archive/year rollover tool where by courses are backed up, transferred to a different Moodle and then restored. It all works except that in my current version category enrollments aren't being backed up and then restored. 

Any thoughts? 

Thanks

Mark