Log in with your old email address and password.
From the menu on the right, choose "Update Listing".
From this menu you can update all your text details, including the email address to which enquiries are sent.
Please be very, very careful that enter the new email address correctly.
Maybe once done, send yourself an enquiry from your full page advert?
It is not unknown for people to mistype .co.uk for .com, especially on hotmail and aol email addresses, etc.