Many thanks for all your help and comments.
Have tried un DCPROMO and re DCPROMO as suggested.
No FRS errors in Event Log.
Am checking MS Support article as suggested by djm968 but heavy going.
Servers have been running for months.
Servers can see each other and replication connection objects fine and checked. Servers are sending and receiving files inside NTFRS pre-install directory, staging directory, staging areas directory but unable to move same files inside policies or scripts folders. Reports sharing violations and morphed directories which we can’t see and resolve. Also reports files in ID Table without proper parent.
NETLOGON and SYSVOL share exist on all servers.
Am intrigued by randle’s mention of AD password and would appreciate clarification.