Ok, I was right first time around - perhaps I didn't make myself clear.
I have just created a master enrollment course in 1.5 (just a normal course)
I created lots of unit courses and made them meta courses. In the add pupils section in a meta course you pick the normal course it gets it's enrollments from - in this case my master enrollment course.
My test user enrolled in the normal (master) course and found himself immediately a member of all of the unit (meta) courses.
I know this isn't how it was designed to be used but I'm sure this is how most people will use it. I have attached an image to clarify how I will use this feature.
One final beg - please change the name of meta courses to make it less confusing before 1.5 appears 
. Something along the lines of inherited enrollments???
