Thanks for the reply.
My school's domain greenwayschool.co.uk is hosted externally with a hosting co.
With the Zimbra box currently all I am trying to do is retrieve the pop3 email from the external mail server and deliver it to my zimbra box which is currently on my home dsl connection.
Once running correctly I will move it to my school where we will use it for school email and calendering.
There is more info going back through the post.
Thanks for your interest.