Further help required!
Further to above, have added the email behaviour to the teacher-registration page successfully. Added the file attachment fine and removed the unneeded file upload behaviour. EMails triggering fine, but I cannot, for the love of god, get this captcha to work. It just seems to let the form send whatever. Have tried to follow your guide, and form action is pointing at teacher-registration.php but it wont validate. Also, I added a quick "incorrect" SHOW IF FAILS behaviour and that shows on the page regardless.
Pleeeease! Where am I going wrong. So need to put this to bed :)