ok so it may be working but still have an issue,
Once I logged in with a user account on the machine and that user was added through "add local domain users" the encyption eventually started.
When I restarted I was able to enter the usernames that are iherited from the secure group I have assigned to the container above the workstations.
However, After encypting another machine and trying some accounts from the inherited secure group they were not picking up the passwords already set previosuly on the other machine. is there are setting I have missed? I was under the impression once a password is set for a user it should use the same details on any machine that user is assigned to. This is currently not happening.