Here you go:
#
# Access Control List. Used for LDAP bind.
#
# NOTE: Every domain have a administrator. e.g.
# Domain Name: 'intra.abc-ltd.co.uk'
# Admin Name: mail=postmaster@intra.abc-ltd.co.uk, domainName=intra.abc-ltd.co.uk, o=domains,dc=intra,dc=abc-ltd,dc=co.uk
#
#
# Set permission for LDAP attrs.
#
access to attrs="userPassword,mailForwardingAddress"
by anonymous auth
by self write
by dn.exact="cn=vmail,dc=intra,dc=abc-ltd,dc=co.uk" read
by dn.exact="cn=vmailadmin,dc=intra,dc=abc-ltd,dc=co.uk" write
by dn.regex="mail=postmaster@([^,]+),domainName=$1,o=domains,dc=intra,dc=abc-ltd,dc=co.uk" write
by users none
access to attrs="cn,sn,telephoneNumber"
by anonymous auth
by self write
by dn.exact="cn=vmail,dc=intra,dc=abc-ltd,dc=co.uk" read
by dn.exact="cn=vmailadmin,dc=intra,dc=abc-ltd,dc=co.uk" write
by dn.regex="mail=postmaster@([^,]+),domainName=$1,o=domains,dc=intra,dc=abc-ltd,dc=co.uk" write
by users read
# Domain attrs.
access to attrs="objectclass,domainName,mtaTransport,domainStatus,enabledService,domainSenderBccAddress,domainRecipientBccAddress"
by anonymous auth
by self read
by dn.exact="cn=vmail,dc=intra,dc=abc-ltd,dc=co.uk" read
by dn.exact="cn=vmailadmin,dc=intra,dc=abc-ltd,dc=co.uk" write
by dn.regex="mail=postmaster@([^,]+),domainName=$1,o=domains,dc=intra,dc=abc-ltd,dc=co.uk" write
by users read
# User attrs.
access to attrs="mail,accountStatus,userSenderBccAddress,userRecipientBccAddress,mailForwardingAddress,mailQuota,homeDirectory,mailMessageStore"
by anonymous auth
by self read
by dn.exact="cn=vmail,dc=intra,dc=abc-ltd,dc=co.uk" read
by dn.exact="cn=vmailadmin,dc=intra,dc=abc-ltd,dc=co.uk" write
by dn.regex="mail=postmaster@([^,]+),domainName=$1,o=domains,dc=intra,dc=abc-ltd,dc=co.uk" write
by users read
#
# Set ACL for vmail/vmailadmin.
#
access to dn="cn=vmail,dc=intra,dc=abc-ltd,dc=co.uk"
by anonymous auth
by self write
by dn.exact="cn=vmailadmin,dc=intra,dc=abc-ltd,dc=co.uk" write
by users none
access to dn="cn=vmailadmin,dc=intra,dc=abc-ltd,dc=co.uk"
by anonymous auth
by self write
by users none
#
# Allow users to access their own domain subtree.
#
access to dn.regex="domainName=([^,]+),o=domains,dc=intra,dc=abc-ltd,dc=co.uk$"
by anonymous auth
by self write
by dn.exact="cn=vmail,dc=intra,dc=abc-ltd,dc=co.uk" read
by dn.exact="cn=vmailadmin,dc=intra,dc=abc-ltd,dc=co.uk" write
by dn.regex="mail=postmaster@$1,domainName=$1,o=domains,dc=intra,dc=abc-ltd,dc=co.uk$" write
by dn.regex="mail=[^,]+,domainName=$1,o=domains,dc=intra,dc=abc-ltd,dc=co.uk$" read
by users none
#
# Enable vmail/vmailadmin.
#
access to dn.subtree="o=domains,dc=intra,dc=abc-ltd,dc=co.uk"
by anonymous auth
by self write
by dn.exact="cn=vmail,dc=intra,dc=abc-ltd,dc=co.uk" read
by dn.exact="cn=vmailadmin,dc=intra,dc=abc-ltd,dc=co.uk" write
by dn.regex="mail=[^,]+,domainName=$1,o=domains,dc=intra,dc=abc-ltd,dc=co.uk$" read
by users read
#
# Set permission for "cn=*,dc=intra,dc=abc-ltd,dc=co.uk".
#
access to dn.regex="cn=[^,]+,dc=intra,dc=abc-ltd,dc=co.uk"
by anonymous auth
by self write
by users none
#
# Set default permission.
#
access to *
by anonymous auth
by self write
by users read