Hi John, and thanks for responding.
I'm getting this error:
"Exim configuration file /etc/exim.conf has the wrong owner, group, or mode"
The permissions are correct, but I think I've 'cocked it up' by downloading the file to comment-out the headers_add, because when I load it back in to the /etc directory, the original file(which I renamed to exim.confORIG is showing 'root' next to it (is that indicating where it originated/ownership??) whereas my modded uploaded one is not showing 'root' but a subordinate directory name. Being a newbie to this, I don't know how to (in Putty) carry out the mod to the file 'in-situ'.
Need a bit more guidance if possible.......
many thanks.