So I think Im missing something obvious here.
I set up my mailchimp block to accept only email addresses from people to subscribe to a list.
However, it seems that this only works as described with anonymous users.
If the user is logged in, the block changes into a radio check box with a 'join my list etc' title and a save settings button.
I have placed the box in my header, and wanted to keep the 'email submit field' consistent with all users, no matter the user role or if already subscribed.