For anyone who suffers similar problems but not quite the same, you may find this link useful:
Description of the Outlook 2003 post-Service Pack 3 hotfix package: December 7, 2007
As far as my particular case is concerned... no real progress as yet, we have found some addins in the registry making it possible to re-produce the issue easily when turned on as apposed to off but having said that so does doing the same with BB. Anyway the case has escalated to the MS dev guys now who have sample code and will be taking a closer look at out the Outlook object model deals with these types of addins and perhaps even initiate an urgent product change...