Ondrej Kuznick of the OpenLDAP Project (and Symas) wrote a python script to check the replication status of an OpenLDAP cluster. You can find the project at:
https://git.openldap.org/openldap/syncmonitor
There are many older scripts out there. Ondrej decided that the project needed to provide one that can be publicly discussed and maintained.
The project also contains tools for developing more sophisticated replication monitoring.
Enjoy!