Resolution:
The following steps have been found to work optimally when renaming directors viz:

1) Rename the Secondary and reconfigure the Primary to know about the new Secondary name.

2) Reconfigure all Brokers for the new Secondary Director

3) Alias new Primary Director name to the old one (DNS Alias)

4) Amend all Engine configurations to reflect the new names for the Primary and Secondary Director. Also amend the Daemon configuration using "Configure All Daemons" global actions to reflect the new names for both Directors. All daemons and engines should log in as appropriate at this point.

5) Amend the driver.properties file for all Drivers (or programmatically if you're using the DriverManager API ) to reflect the new name for both Directors.

6) Rename and reconfigure the Primary followed by reconfiguring the primary director setting on all of the Brokers and Secondary.

7) Reconfigure the daemons' director settings back to "default" and remove the alias.

The rationale for renaming the Secondary first is to guide against the fact that engine configuration can not be amended on the Secondary (so needs to be done on the Primary before the name change) and the Brokers may not move as expected to the Secondary if sequence is not done properly.