The reason - some idiot forgot to put a 11pm hands on Big Ben, instead of 10.00pm, and they had to cur away from the clockface.
Is this another one of your made up facts?
No, the original opening title sequence for both News at Ten and The Late News was to have the clock face on screen. News at Ten of course had the hands at 10.00pm, but the Late News didn't have their hands at 11.00pm. Which is why we get the abrupt cut away when the approach Big Ben, and a straight cut into the studio.
The Late News even had an XI brand logo on screen symbolising 11pm. However, for some reason they didn't create a proper version of the titles.
This was the reason why they decided to revert back to the standard ITV News set, and leave News at Ten with the night time sky view and titles on its own, at least until the February 2009 relaunch of the presentation, which saw all ITV News programmes gain the News at Ten studio design.
Information provided to me from someone at ITN a few years a go, when I visited there as part of my Media Studies training.
tweedledum and Woodpecker gave kudos