ES File Explorer (free from Play Store)
Barclays Mobile Banking / Pingit (also free from the Play Store)
1: Open ES Explorer options and make sure you enable 'Up to Root' & 'Root Explorer'.
2: Navigate to '/system/xbin/' and long press on 'SU' and select 'Hide' from the menu.
NOTE: if you update the SuperSU binary, you will need to do step 2 again!
That's it! No more messing around. You don't need to touch anything else before or after you open the app like temp unroot/hide root. I dont know if Barclays can solve that with an update so I don't plan on updating the app. I'm not a coder and don't know a lot about the technical details of Android so if you run in to problems I can only TRY to help you.
Sent from my GT-I9300 using xda premium