Last Known No Good
Seems to me they're probably in a real bind by now, in any 'normal' upgrade snafu you would be reassured that you could roll back to the last known good position and back out gracefully. But because the last known good was on the Lloyds Bank system any roll back would involve rolling back all of the Lloyd systems as well......
Measuring the complexity of the systems and issue probably means there is never a snapshot in time that they can actually ever accurately roll back to, so the only way to perform a migration of this nature is the equivalent of running two trains in parallel and throwing the TSB customer accounts across the gap and hoping that they land up in the equivalent carriage and seat.
Biting the hand that feeds IT
