"the configuration of your mailhost"??!! What mailhost?
It is outlook.com, including hotmail.com and outlook.com plus others. There is no "configuration"; it is what it is. You click on the corner of the message and say "Show Original" and the output of that is what you paste into SpamCop. Outlook recently changed the contents of this, presumably because of the way mail routes through their internal systems, possibly between hotmail and outlook domains. Now, everything apparently comes "from" outlook, which is nonsense. Strip that part out, and it finally "sees" the correct source.
Now, on that basis, what "configuration" do you think we should be "checking" or tweaking? Because when you say "check" I was kind of assuming you'd give some advice on what to check and what to change, because I wouldn't have a single clue what configuration could be changed to fix this.
However, I'm assuming that as I don't have a mailhost, as outlook.com handles all that for me, we need spamcop to find the correct part of the headings for us without having to do some manual filtering all the time. Hotmail and outlook.com are pretty big and we won't change the way they configure things. So either spamcop adjusts for them, or spamcop can't help a large percentage of the webmail users out there.