Really? How so?
All prisoners have an official date of release. It's not difficult to work out at all.
And DVLA have nothing to do with criminal records. They'd only have to update their own records and that can be done once release has occurred. Again, not a big problem - that sort of data exchange goes on every day.
The Prison Service has always been a law unto itself when it comes to releasing prisoners.
I know the DVLA has nothing to do with criminal records - that is precisely why this measure may prove difficult to administer.
I agree the 'data exchange' should work, but experience suggests otherwise.