I've been googling and turned up this.
Forced silent auto reconnection:
When a server has been unavailable (offline mode) and then becomes available again for connection, Offline Files Client Side Caching tries to transition that server to online mode if all the following conditions are true: #
• There are no offline changes for that server on the local computer.
• There are no open file handles for that server on the local computer.
• The server is accessed over a “fast” link.
You can adjust the definition of “slow” and “fast” by using the SlowLinkSpeed Offline Files policy. With this hotfix, you can configure Offline Files Client Side Caching to ignore these conditions and transition the server to online mode regardless of whether these conditions exist. To do this, follow these steps:
1. Click Start, click Run, type REGEDIT, and then click OK.
2. Locate and click the following registry subkey:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Curr entVersion\NetCache
3. Click Edit, point to New, and then click DWORD Value.
4. Type SilentForcedAutoReconnect, and then press ENTER to name the value.
5. Double-click SilentForcedAutoReconnect.
6. In the Value data box, type 1, and then click OK.
Source
Going to try that tomorow.
Mike.