Comments showing on pages but not showing on posts

Hi folks,

I can't get the comments form to show on posts on Multi Site with Buddypress Social theme and the Membership plugin..

The Comment form shows on the post editor but there's nothing on the posts themselves.

Comments seem to work fine on Pages.

I've tried disabling all plugins but it made no difference.

I'd appreciate your help as it's holding me back from launching the site.

Thanks