Mytholmroydartsfestival on "[Plugin: MailChimp for WordPress] Mailchimp for WP lite checkbox not updating registration form"

I have created a registration page on my web site and embedded the registration form [wp-members page="register"]

I have the Mailchimp for WP lite plugin which is working fine. I have ticked the checkbox for the registration form and saved the page. There is no checkbox on my registration page. http://mytholmroydartsfestival.org.uk/participate/register-to-enter-an-event/

What am I doing wrong?

Thanks

Jane

https://wordpress.org/plugins/mailchimp-for-wp/