I've posted before that I find this surprising, but here is Warwick's Registrar again quite clearly saying that he wants to outsource Registry functions, and expects to join with other institutions in doing so.
I can't help but see this as evidence that the 'traditional' university administrator (and I am one of those) is losing status in the sector. You don't outsource high-status activities which are central to the career paths or self-identities of senior managers. You do outsource cleaning and security. I'm also surprised because data management and data returns are so full of risk to universities at the moment (unlike, say, cleaning) that I would have expected institutions to be determined to keep close control.
That said the purely technical prospects for this kind of shared service are good, and the private providers in particular should really welcome a service like this (if it was genuinely cost-effective). I wonder if that is part of the model?