It's feasible that retaining the separate UTV name for at least long enough to see the 60th anniversary come and go was always the intention, but with the potential to drop it at any point thereafter.
No doubt there'll be special celebratory feature items in UTV Live during the anniversary week itself. To then rebrand as ITV, say, the very following week would be too jarring. But rebranding about 8 weeks later (coinciding with the end of the ITV Creates idents) would seem logical.
We'll just have to wait and see.
I'm still a European.