It appears that First Direct are giving BlackBerry 10 a serious go, as despite using the Android runtime - they are open to developing the app further:
We know that you like to manage your money when you're ‘on the go', that's why we've listened to your feedback and now provided our app for BlackBerry 10. We want to assess the adoption of the app by our customers who use BlackBerry 10 to help provide insight for our future digital developments.
If you are a First Direct customer, go and grab it now.
More information / download Banking on the Go