Tweaking possibilities

OK - so presumably it's possible as the senders email address is collected through 'from_email" gtbfieldid=".....' as part of the Public Frontend Plugin.

However, to get it to work would require changes to the code for it to be send as part of the email. Correct?

Thanks

Yes, code changes are required.

Maybe it is better and more easy to create a form on a static Joomla page that uses uddeIM API to create a PM (with notification).