Blocked Access as Member Admin

I'm trying to configure membership for a new site we're deploying and I keep hitting a brick wall despite having followed the manual.

I have 3 levels created; one a free access level that should cover all of the site pages. The next level should allow all staff members to access BuddyPress, most posts and some groups. The third level should allow managers only to access everything.

There is no subscription cost, but what is happening is that I've ended up blocked from viewing the BuddyPress section (and I'm the member admin, so that's not good) and portions of the site.

Should I be using a different tool for this? Essentially what we're using it for is to create a private social network for the business, but I don't want the general public unable to see site content.

Suggestions would be very appreciated!

Thanks -

Sue