Membership Plugin - restricting access by catagory

OK... I have a video site, and I want to create Premium video content that my website users need to pay for...

I have added two Access levels... one is Base User and one is 2012 AUC Premium (subscribers content.)

I have then created a 2012 AUC Subscription with the 2012 AUC Premium access level... and in the options I have set in the Stranger Settings to have Base User access.

I have created a category 2013 AUC Premium Content and I place the video posts into this category.

I have set the Basic User access level to have a negative rule of 2013 AUC Premium content...

However Basic users (or strangers) can not see the category listings when they visit the site... but if they go directly to the URL of the video that is in the category they can see the content. This doesn't work for me as people will share the links with non subscribers...

Keen for any suggestions as to why this is not working as I expect... and what I can do to fix it...