How do I disable the standard WordPress registration when using Pro Sites?

I am setting up pro sites on a mutistie Network, I want to allow users to register on my default site via the prosites plugin. However users can still register to my website via the default WordPress / Buddy Press registration page.

This wouldn’t normally be an issue but I am getting quite a lot of spam users registering and posting spam comments across my site.

When I disable registration via the Network setting Pro Site functionality disapears and no one can register to my site regardless of if they try via pro site or standard registration.

When I enable registration via pro sites they can register via two ways:

1: mydomain.comregister

2: mydomain.compro-site

Is there any way to disable the default registration or have it replaced with the Pro Site plugin to handle registrations?

I have been stuck with this issue for well over two months now and I am finally calling for help.

Thanks in advance.