Unless your car player support cdrw media (which can be rewritten many times) then you can use cdrw.
To know all is to understand, as they say!! If I had followed the original posting (Listerman) on this question more closely I would have seen that 'data' was being mentioned all the way along the line.
I haven't had time to try again but I will. Do I have to use a new CD or will I be able to carry on with the one I have already started?? bearing in mind that I was trying to cut down on how many CDs I had to carry around.