The e-mail address you used to register with us is displayed under ‘Contact details’ in Menu > My profile.
If you are not yet logged in and cannot remember which email address you used to create your account, first click on the login button and then on 'forgot password?'. On the next screen, try entering your various email addresses to see if you receive a password reminder email from us. If you are registered with us using the email address you entered, you will receive an email allowing you to request a new password. After creating this password, you can log in with this email address and the newly created password.