Buddypress links on nav bar don't go to subdomain site but main domain?

Hi there

I have a Buddypress on a subdomain and really like the Blogs MU theme that I spent some time configuring. Then I noticed quite late on that the HOME, COMMUNITY (and sub bp elements) all link to maindomain.com vs buddy.maindomain.com - I looked at navigation.php (I am not using the child but the parent) and noticed it is polling the 'domain' it is on, so wondering what is going wrong here?

Thanks in advance