ZCM 11.1a (sles11), win7 32 ir9a client, nw65sp8 server user homes

I am having major problems with DLU/roaming profiles.

After a few logins on a clean profile users lose their background bitmap, black screen only (machines are ms licenced) and we can't launch groupwise which gives the message
Groupwise id not properly installed. The groupwise components could not be initialised.
Please run groupwise setup, or contact your system administrator.
There are other symptons as well, lose aero capability whick kills enabling apps which require it (zoomtext, magnifier).

I have checked the usual gw profile issues address book etc and these seem to be ok.

I have noticed that the local user is not always deleted by zen when you logout and log back in again as a local user (Manage existing user account/Volatile user checked), and that all the users policies are not on when they login, ie I immediatly look at the Zen agent and see that all of the user-assigned policies are not there, a refresh will then add the policy to the user and it does request a reboot if the policy is set to reboot.

I can (sometimes) replicate the error by logging in as a member of staff, then a student and then back to the member of staff - this is when the pofile breaks and stays broken until the profile is recreated on the users network home drive. This fails wherever you are a local user or administrator, machine or network rights have not significance on the issue.
Staff and students have a different dlu and roaming policy, I am wondering wherever this has any significance.

Registry dumps and zcm logs are not reporing anything out of the ordinary.

Anybody have any ideas on this as we are a bit stuck.