Oddly I was on pre-Creators Update and kept getting messages from Barclays that the app is broken in Creators update and to wait. Then I found the app kept crashing on entering the PIN, so I gave up and updated to Creators anyway, and now the app works fine even though the last message they sent indicated they were still working on a fix.
Anyway, nice to see one major bank still acknowledges the existence of Windows Phone, and it's still a very nice example of a Win app.