When you download a backup on to a new phone some of your details are unexpectedly being transferred across from your old phone by Apple. This data is causing our app to crash when you try and launch it, we are aware of the issue and are working hard to ensure it is resolved in a future release.
To continue using mobile banking please delete the app from your phone and download it again from the App Store, this will fix the issue. You will need to re-register for the app.