Default Unrooting...

So basically i would like to run vanilla android on my n9005... But barclays in their never ending quest to annoy everyone, prevent accessing and using the banking app while being rooted. SO, would just like to know if this is possible:

1. Flash AOSP ROM.
2. Use Superuser to Unroot.
3. Continue to use phone as normal with no root but be on vanilla android.
4. Because i'd have no root, use barclays app as normal.

Any one done this before or know if it'd work?