You need to 'claim' the email address for yourself as it is attached to multiple FAN records. In order to do that, return to the Whole Game System home page and then click on 'Forgotten Email?' 

You'll then be able to enter your FAN and password. Click 'Continue' and confirm your email address. You'll then be informed that the email is held on multiple accounts and you'll be invited to type in your email address and get sent a code, which will be sent to the email address. Type the code on the next screen and click 'Verify Code' and you will then have claimed the email address,

The next time you log in, you'll be able to do so by using your email address and password.

You can watch a walk-through video of the process or see step-by-step screen grabs here: https://grassrootstechnology.freshdesk.com/support/solutions/articles/48001080323-wgs-login-my-email-exists-on-more-than-one-account.