Hi all,
I have solved this issue. Aside from originally (incorrectly) configuring the AUTH_LDAP_GROUP_SEARCH to include the CN of my group, I needed to change the objectClass filter that is documented from the groupOfNames, that everything seems to say to use, to just group.
In the end my AUTH_LDAP_GROUP_SEARCH is now something like: LDAPSearch("OU=Groups,OU=co,DC=example,DC=com", ldap.SCOPE_SUBTREE, "(objectClass=group)")
I hope this helps anyone else who may have the issue now or in the future, this was a rough journey, thank you for the help Milosz.
Best regards, Michael