[Stuart]

It didn't become the official name for a number of years after 1989 though.

The 'Broadcasting Act 1990' was already working its way through Parliament at the time, which changed the name of the network. It was therefore already the official name of the franchises they were intending to bid for when it passed.

I think the new logo was intended to represent that new name as a more unified network, without losing 'ITV' in the process.