Thanks, Christian.
I have done that, but it has made no difference.
It still doesn't alter the fact that, regardless of what the ISP does or
doesn't allow, I cannot find anywhere in Icedove to change the "from" email
address in outgoing mail.
My husband is currently running the same version of Icedove at the same ISP as
the OldISP. He also has a googlemail account, but is not setup to use it as
a send-from address. Since the problem PC _was_ sending quite happily using
a Gmail address, it must have accepted the setting. But I can't find
anywhere to change it on either computer.
It also follows that I *did* know how to do it. :-(
Lisi