ITV did next to nothing on the night itself regarding the Manchester Arena bombing IIRC.
Because they were off air. The scale of what had happened only became clear very late at night.
ITV News do have the capability of late night Newsflashes. The London Bridge terror attack in 2017 came to light close to midnight, and a Newflash came to air then, about two hours since that day's final bulletin. And Julie returned for another Newsflash on Sunday morning.
For the Manchester Arena attacks, the details were very sketchy as to what exactly happened for most of the night which the news channels mostly struggled with and the details only really came to light once the breakfast programmes came to air. ITV News took over coverage that whole morning, so I think they did as well as they could with that.
Central News South January 9th 1989 - December 3rd 2006