Hi Hilary and sorry about the delay before replying,
Yes we are using SharePoint in Office 365 and unfortunately Power Automate is not an option in this situation. I appreciate that Automate/Flow offers a greater levels of control but this is a kind of 'fix it if you can' (free of charge of course) situation with a company who I worked with about 3 years ago. Why it has come to the surface as an issue now I don't know, but perhaps different personnel are the cause.
I did consider backing the workflows into new 'Save' Views of the InfoPath functionality but that raises different problems and as the rest of things is working OK I don't want to fiddle unless I have to.
As I can add the name of the true 'send from' person in the body of the email (and other stuff as well), then that might have to be enough.
Thanks for replying though.
Regards Alan C.