Are you talking about the headers or the add notes into email body?

Both ;-(

Aren’t either of them present?

Nope ;-(

If you put avast and maildirect smtp port at 25, what happens?

I get the error message that you see at the bottom of here:
www.goodhorizons.com/avast (Ignore the top image for now)

Can you check with TCPView application what is using the port 25?

Just done that, the results are the 2nd and 3rd images from the top on here:
www.goodhorizons.com/avast (The entries kept jumping around a bit and they wouldn’t fit onto one page, hence the 2 images)

The help is appreciated.