Ok - trying to help myself a little here and understand MacOS logs, I see in the console, under 'opendirectoryd.log';
2012-07-05 08:54:40.544 BST - opendirectoryd (build 172.13) launched...
2012-07-05 08:54:40.546 BST - Logging level limit changed to 'error'
2012-07-05 08:54:40.572 BST - Initialize trigger support
2012-07-05 08:54:40.574 BST - Registered node with name '/Active Directory' as hidden
2012-07-05 08:54:40.574 BST - Registered node with name '/Configure' as hidden
2012-07-05 08:54:40.575 BST - Discovered configuration for node name '/Contacts' at path '/Library/Preferences/OpenDirectory/Configurations//Contacts.plist'
2012-07-05 08:54:40.575 BST - Registered node with name '/Contacts'
2012-07-05 08:54:40.576 BST - Registered node with name '/LDAPv3' as hidden
2012-07-05 08:54:40.579 BST - Registered node with name '/Local' as hidden
2012-07-05 08:54:40.580 BST - Registered node with name '/NIS' as hidden
2012-07-05 08:54:40.581 BST - Discovered configuration for node name '/Search' at path '/Library/Preferences/OpenDirectory/Configurations//Search.plist'
2012-07-05 08:54:40.581 BST - Registered node with name '/Search'
2012-07-05 08:54:40.584 BST - Discovered configuration for node name '/LDAPv3/localhost' at path '/Library/Preferences/OpenDirectory/Configurations/LDAPv3/localhost.plist'
2012-07-05 08:54:40.584 BST - Registered subnode with name '/LDAPv3/localhost'
2012-07-05 08:54:40.588 BST - Loaded bundle at path '/System/Library/OpenDirectory/Modules/legacy.bundle'
2012-07-05 08:54:40.594 BST - Loaded bundle at path '/System/Library/OpenDirectory/Modules/search.bundle'
2012-07-05 08:54:41.598 BST - '/Search' has registered, loading additional services
2012-07-05 08:54:41.598 BST - Initialize augmentation support
2012-07-05 08:54:41.606 BST - Loaded bundle at path '/System/Library/OpenDirectory/Modules/SystemCache.bundle'
2012-07-05 08:54:41.611 BST - Successfully registered for Kernel identity service requests
2012-07-05 08:54:41.617 BST - Loaded bundle at path '/System/Library/OpenDirectory/Modules/PlistFile.bundle'
2012-07-05 08:54:41.620 BST - Loaded bundle at path '/System/Library/OpenDirectory/Modules/FDESupport.bundle'
2012-07-05 08:54:41.671 BST - Loaded bundle at path '/System/Library/OpenDirectory/Modules/ConfigurationProfiles.bundle'
2012-07-05 08:54:41.672 BST - Registered subnode with name '/Local/Default'
2012-07-05 08:54:41.680 BST - Loaded bundle at path '/System/Library/OpenDirectory/Modules/ldap.bundle'
2012-07-05 08:54:41.691 BST - Loaded bundle at path '/System/Library/OpenDirectory/Modules/AppleODClient.bundle'
2012-07-05 08:56:14.571 BST - failed to retrieve password for credential
2012-07-05 08:56:19.581 BST - failed to retrieve password for credential
2012-07-05 08:56:29.593 BST - failed to retrieve password for credential
2012-07-05 08:56:34.579 BST - failed to retrieve password for credential
2012-07-05 08:56:39.589 BST - failed to retrieve password for credential
2012-07-05 08:56:49.601 BST - failed to retrieve password for credential
2012-07-05 08:57:04.610 BST - failed to retrieve password for credential
2012-07-05 08:57:24.621 BST - failed to retrieve password for credential
2012-07-05 08:57:49.626 BST - failed to retrieve password for credential
This reapeats everyday all day every 30 seconds. :*(