I can answer my own query ........

* Share the folder for whatever account a local or network Dinesat client will be using.

* In the Dinesat Server Config utility, create a new Storage, and enter br /> - For the Storage actual path use the UNC path e.g. e.g. "\\[Computer Name]\[Share Name]\"
- The Storage UNC path is as expected e.g. "\\[Computer Name]\[Share Name]\"

* Change the logon account of the following "Dinesat Pro Radio 10" services from System to the appropriate account for the network share (Control Panel / Administrative Tools).

- FTP Server
- HTTP Server
- Server
- Soap Server
- Web Server

Reason - a Windows Service running on the local System account can't access network resources outside the PC.

LEAVE "Dinesat Server Starter" on the System account, otherwise it can't start the other services.

It's possible the different Service logon account may not have the right privileges to open the SQL databases. This can happen even when a User account has been given "Full Control" of C:\Program Files (x86)\Dinesat Pro Radio 10. You'll have to give the User access to each *.ldf / *.mdf manually.
This problem was observed, but not actually proved to be the fix, as I finally decided using a network share my be problematic if the audio storage went offline but the server stayed up. Even if a Backup Server is configured, Dinesat does not alert the user if the its audio disappears. It just starts looping the last audio buffer, and then stops with no error dialog at all. But loss of the server does eventually produce a dialog, flagging the change to the Backup Server. So they should probably be on the same Windows PC, but the audio could be on a different drive/partition.