Ah! I see now! I had only set it up to allow myslef & another exchange user to use that at all (including relaying perms).
No-one ever told me you needed SMTP to receive mail, I really thought it was only for sending :/ my bad.
Also 'silly accounts like test:test' i have exchange installed and before that didn't create any accounts. So now, the only way to set passwords is to have those big bad boy heavily secure passwords.
Also I rarely ever have accounts on a box that aren't used
250 2.1.0 email@example.com.........Sender OK
Guessing that means it's fine now?